diff --git a/userspace/engine/lua/rule_loader.lua b/userspace/engine/lua/rule_loader.lua
index 0f4d828e..7a2fe997 100644
--- a/userspace/engine/lua/rule_loader.lua
+++ b/userspace/engine/lua/rule_loader.lua
@@ -222,7 +222,24 @@ function load_rules(rules_content, rules_mgr, verbose, all_events, extra, replac
 	    end
 	 end
 
-	 state.lists_by_name[v['list']] = v
+	 -- Possibly append to an existing list
+	 append = false
+
+	 if v['append'] then
+	    append = v['append']
+	 end
+
+	 if append then
+	    if state.lists_by_name[v['list']] == nil then
+	       error ("List " ..v['list'].. " has 'append' key but no list by that name already exists")
+	    end
+
+	    for i, elem in ipairs(v['items']) do
+	       table.insert(state.lists_by_name[v['list']]['items'], elem)
+	    end
+	 else
+	    state.lists_by_name[v['list']] = v
+	 end
 
       elseif (v['rule']) then