diff --git a/OpenSim/Services/GridService/HypergridLinker.cs b/OpenSim/Services/GridService/HypergridLinker.cs
index c273d21229..50da1bd729 100644
--- a/OpenSim/Services/GridService/HypergridLinker.cs
+++ b/OpenSim/Services/GridService/HypergridLinker.cs
@@ -27,6 +27,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Net;
 using System.Reflection;
 using System.Xml;
@@ -154,6 +155,11 @@ namespace OpenSim.Services.GridService
 
         // From the command line link-region
         public GridRegion TryLinkRegionToCoords(UUID scopeID, string mapName, int xloc, int yloc, out string reason)
+        {
+            return TryLinkRegionToCoords(scopeID, mapName, xloc, yloc, UUID.Zero, out reason);
+        }
+
+        public GridRegion TryLinkRegionToCoords(UUID scopeID, string mapName, int xloc, int yloc, UUID ownerID, out string reason)
         {
             reason = string.Empty;
             string host = "127.0.0.1";
@@ -190,7 +196,7 @@ namespace OpenSim.Services.GridService
             //}
 
             GridRegion regInfo;
-            bool success = TryCreateLink(scopeID, xloc, yloc, regionName, port, host, out regInfo, out reason);
+            bool success = TryCreateLink(scopeID, xloc, yloc, regionName, port, host, ownerID, out regInfo, out reason);
             if (success)
             {
                 regInfo.RegionName = mapName;
@@ -200,12 +206,12 @@ namespace OpenSim.Services.GridService
             return null;
         }
                 
-        public bool TryCreateLink(UUID scopeID, int xloc, int yloc, string externalRegionName, uint externalPort, string externalHostName, out GridRegion regInfo, out string reason)
+        public bool TryCreateLink(UUID scopeID, int xloc, int yloc, string externalRegionName, uint externalPort, string externalHostName, UUID ownerID, out GridRegion regInfo, out string reason)
         {
-            return TryCreateLink(scopeID, xloc, yloc, externalRegionName, externalPort, externalHostName, null, out regInfo, out reason);
+            return TryCreateLink(scopeID, xloc, yloc, externalRegionName, externalPort, externalHostName, null, ownerID, out regInfo, out reason);
         }
         
-        public bool TryCreateLink(UUID scopeID, int xloc, int yloc, string externalRegionName, uint externalPort, string externalHostName, string serverURI, out GridRegion regInfo, out string reason)
+        public bool TryCreateLink(UUID scopeID, int xloc, int yloc, string externalRegionName, uint externalPort, string externalHostName, string serverURI, UUID ownerID, out GridRegion regInfo, out string reason)
         {
             m_log.DebugFormat("[HYPERGRID LINKER]: Link to {0}:{1}:{2}, in {3}-{4}", externalHostName, externalPort, externalRegionName, xloc, yloc);
 
@@ -225,6 +231,16 @@ namespace OpenSim.Services.GridService
             regInfo.RegionLocX = xloc;
             regInfo.RegionLocY = yloc;
             regInfo.ScopeID = scopeID;
+            regInfo.EstateOwner = ownerID;
+
+            // Check for free coordinates
+            GridRegion region = m_GridService.GetRegionByPosition(regInfo.ScopeID, regInfo.RegionLocX, regInfo.RegionLocY);
+            if (region != null)
+            {
+                m_log.WarnFormat("[HYPERGRID LINKER]: Coordinates {0}-{1} are already occupied by region {2} with uuid {3}", regInfo.RegionLocX, regInfo.RegionLocY, region.RegionName, region.RegionID);
+                reason = "Coordinates are already in use";
+                return false;
+            }
 
             try
             {
@@ -247,11 +263,11 @@ namespace OpenSim.Services.GridService
 
             if (regionID != UUID.Zero)
             {
-                GridRegion r = m_GridService.GetRegionByUUID(scopeID, regionID);
-                if (r != null)
+                region = m_GridService.GetRegionByUUID(scopeID, regionID);
+                if (region != null)
                 {
-                    m_log.DebugFormat("[HYPERGRID LINKER]: Region already exists in coordinates {0} {1}", r.RegionLocX / Constants.RegionSize, r.RegionLocY / Constants.RegionSize);
-                    regInfo = r;
+                    m_log.DebugFormat("[HYPERGRID LINKER]: Region already exists in coordinates {0} {1}", region.RegionLocX / Constants.RegionSize, region.RegionLocY / Constants.RegionSize);
+                    regInfo = region;
                     return true;
                 }
 
@@ -366,17 +382,8 @@ namespace OpenSim.Services.GridService
             {
                 // Check for regions which are not linked regions
                 List<GridRegion> hyperlinks = m_GridService.GetHyperlinks(m_ScopeID);
-                // would like to use .Except, but doesn't seem to exist
-                //IEnumerable<GridRegion> availableRegions = regions.Except(hyperlinks);
-                List<GridRegion> availableRegions = regions.FindAll(delegate(GridRegion region) 
-                {
-                    // Ewww! n^2
-                    if (hyperlinks.Find(delegate(GridRegion r) { return r.RegionID == region.RegionID; }) == null) // not hyperlink. good.
-                        return true;
-
-                    return false;
-                });
-                if (availableRegions.Count == 0)
+                IEnumerable<GridRegion> availableRegions = regions.Except(hyperlinks);
+                if (availableRegions.Count() == 0)
                     return false;
             }
 
@@ -458,7 +465,7 @@ namespace OpenSim.Services.GridService
                 remoteName = cmdparams[3];
             string reason = string.Empty;
             GridRegion regInfo;
-            TryCreateLink(UUID.Zero, xloc, yloc, remoteName, 0, null, serverURI, out regInfo, out reason);
+            TryCreateLink(UUID.Zero, xloc, yloc, remoteName, 0, null, serverURI, UUID.Zero, out regInfo, out reason);
         }
 
         private void RunHGCommand(string command, string[] cmdparams)
@@ -571,7 +578,7 @@ namespace OpenSim.Services.GridService
                     xloc = xloc * (int)Constants.RegionSize;
                     yloc = yloc * (int)Constants.RegionSize;
                     string reason = string.Empty;
-                    if (TryCreateLink(UUID.Zero, xloc, yloc, "", externalPort, externalHostName, out regInfo, out reason))
+                    if (TryCreateLink(UUID.Zero, xloc, yloc, "", externalPort, externalHostName, UUID.Zero, out regInfo, out reason))
                     {
                         if (cmdparams.Length >= 5)
                         {
@@ -673,8 +680,7 @@ namespace OpenSim.Services.GridService
                 xloc = xloc * (int)Constants.RegionSize;
                 yloc = yloc * (int)Constants.RegionSize;
                 string reason = string.Empty;
-                if (TryCreateLink(UUID.Zero, xloc, yloc, "", externalPort,
-                                                     externalHostName, out regInfo, out reason))
+                if (TryCreateLink(UUID.Zero, xloc, yloc, "", externalPort, externalHostName, UUID.Zero, out regInfo, out reason))
                 {
                     regInfo.RegionName = config.GetString("localName", "");
                 }
diff --git a/prebuild.xml b/prebuild.xml
index dd4a5769e7..c6eb65a790 100644
--- a/prebuild.xml
+++ b/prebuild.xml
@@ -1084,6 +1084,7 @@
 
       <ReferencePath>../../../bin/</ReferencePath>
       <Reference name="System"/>
+      <Reference name="System.Core"/>
       <Reference name="System.Xml"/>
       <Reference name="OpenMetaverseTypes" path="../../../bin/"/>
       <Reference name="OpenMetaverse" path="../../../bin/"/>