diff --git a/src/main/java/org/openstreetmap/josm/plugins/mapwithai/commands/MergeAddressBuildings.java b/src/main/java/org/openstreetmap/josm/plugins/mapwithai/commands/MergeAddressBuildings.java
index 3e91a39..3238d6a 100644
--- a/src/main/java/org/openstreetmap/josm/plugins/mapwithai/commands/MergeAddressBuildings.java
+++ b/src/main/java/org/openstreetmap/josm/plugins/mapwithai/commands/MergeAddressBuildings.java
@@ -8,8 +8,11 @@ import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
+import java.util.Objects;
 import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
+import org.openstreetmap.josm.command.ChangePropertyCommand;
 import org.openstreetmap.josm.command.Command;
 import org.openstreetmap.josm.command.SequenceCommand;
 import org.openstreetmap.josm.data.osm.DataSet;
@@ -31,6 +34,7 @@ import org.openstreetmap.josm.tools.Geometry;
  */
 public class MergeAddressBuildings extends AbstractConflationCommand {
     public static final String KEY = "building";
+    public static final String SOURCE = "source";
 
     public MergeAddressBuildings(DataSet data) {
         super(data);
@@ -85,16 +89,27 @@ public class MergeAddressBuildings extends AbstractConflationCommand {
         if (nodesWithAddresses.size() == 1
                 && nodesWithAddresses.parallelStream().allMatch(n -> n.getParentWays().isEmpty())) {
             String currentKey = null;
+            Node node = nodesWithAddresses.get(0);
+            List<String> sources = new ArrayList<>();
             try {
                 // Remove the key to avoid the popup from utilsplugin2
                 currentKey = object.get(KEY);
+                sources.add(object.get(SOURCE));
                 object.remove(KEY);
-                GuiHelper.runInEDTAndWait(() -> commandList
-                        .add(ReplaceGeometryUtils.buildUpgradeNodeCommand(nodesWithAddresses.get(0), object)));
+                object.remove(SOURCE);
+                GuiHelper.runInEDTAndWait(
+                        () -> commandList.add(ReplaceGeometryUtils.buildUpgradeNodeCommand(node, object)));
             } finally {
                 if (currentKey != null) {
                     object.put(KEY, currentKey);
                 }
+                sources.add(node.get(SOURCE));
+                sources.removeIf(Objects::isNull);
+                sources = sources.stream().flatMap(source -> Stream.of(source.split(";", 0))).distinct()
+                        .filter(Objects::nonNull).sorted().collect(Collectors.toList());
+                if (!sources.isEmpty()) {
+                    commandList.add(new ChangePropertyCommand(object, SOURCE, String.join(";", sources)));
+                }
             }
         }
         return commandList;
diff --git a/src/main/java/org/openstreetmap/josm/plugins/mapwithai/commands/MergeBuildingAddress.java b/src/main/java/org/openstreetmap/josm/plugins/mapwithai/commands/MergeBuildingAddress.java
index 791d439..edb90a3 100644
--- a/src/main/java/org/openstreetmap/josm/plugins/mapwithai/commands/MergeBuildingAddress.java
+++ b/src/main/java/org/openstreetmap/josm/plugins/mapwithai/commands/MergeBuildingAddress.java
@@ -8,7 +8,9 @@ import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
+import java.util.Objects;
 import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 import org.openstreetmap.josm.command.ChangePropertyCommand;
 import org.openstreetmap.josm.command.Command;
@@ -92,12 +94,27 @@ public class MergeBuildingAddress extends AbstractConflationCommand {
                 .filter(prim -> checkInside(node, prim)).collect(Collectors.toList());
 
         final List<Command> commandList = new ArrayList<>();
+        List<String> sources = new ArrayList<>();
+        OsmPrimitive object = null;
+        sources.add(node.get(MergeAddressBuildings.SOURCE));
         if (possibleDuplicates.size() == 1) {
             commandList.add(new ChangePropertyCommand(possibleDuplicates, node.getKeys()));
             commandList.add(DeleteCommand.delete(Collections.singleton(node)));
+            object = possibleDuplicates.get(0);
         } else if (buildings.size() == 1 && getAddressPoints(buildings.get(0)).size() == 1) {
             commandList.add(new ChangePropertyCommand(buildings, node.getKeys()));
             commandList.add(DeleteCommand.delete(Collections.singleton(node)));
+            object = buildings.get(0);
+        }
+        if (object != null) {
+            sources.add(object.get(MergeAddressBuildings.SOURCE));
+        }
+
+        sources.removeIf(Objects::isNull);
+        sources = sources.stream().flatMap(source -> Stream.of(source.split(";", 0))).distinct()
+                .filter(Objects::nonNull).sorted().collect(Collectors.toList());
+        if (!sources.isEmpty() && object != null) {
+            commandList.add(new ChangePropertyCommand(object, MergeAddressBuildings.SOURCE, String.join(";", sources)));
         }
 
         return commandList;