diff --git a/Tasks/CombineAddresses.cs b/Tasks/CombineAddresses.cs
index e20a194..324af2e 100644
--- a/Tasks/CombineAddresses.cs
+++ b/Tasks/CombineAddresses.cs
@@ -37,7 +37,8 @@ public class CombineAddresses
     /// <returns></returns>
     public bool CompareAddresses(KasPerson first, KasPerson second, bool only_refsid = false)
     {
-        if (first.refsid == second.refsid) return true;
+        // A refsid of 0 means "missing", so it must not collapse unrelated entries.
+        if (first.refsid != 0 && second.refsid != 0 && first.refsid == second.refsid) return true;
         if (!only_refsid)
             if (first.name == second.name &&
                 first.anrede == second.anrede &&