diff --git a/library/NS_Emulation.ttcnpp b/library/NS_Emulation.ttcnpp
index ca44a02..6d8113c 100644
--- a/library/NS_Emulation.ttcnpp
+++ b/library/NS_Emulation.ttcnpp
@@ -310,30 +310,16 @@
 			/* add index to list of unblocked NSVCs */
 			if (not ischosen(g_nsvcs[i].cfg.provider.ip) or
 			    g_nsvcs[i].cfg.provider.ip.signalling_weight > 0) {
-				g_unblocked_nsvcs_sig := g_unblocked_nsvcs_sig & {i};
+				ro_integer_add_unique(g_unblocked_nsvcs_sig, i);
 			}
 			if (not ischosen(g_nsvcs[i].cfg.provider.ip) or
 			    g_nsvcs[i].cfg.provider.ip.data_weight > 0) {
-				g_unblocked_nsvcs_data := g_unblocked_nsvcs_data & {i};
+				ro_integer_add_unique(g_unblocked_nsvcs_data, i);
 			}
 		} else if (g_nsvcs[i].state == NSVC_S_ALIVE_UNBLOCKED and state != NSVC_S_ALIVE_UNBLOCKED) {
 			/* remove index to list of unblocked NSVCs */
-			var Osmocom_Types.ro_integer new_unblocked_nsvcs_sig := {};
-			for (var integer j := 0; j < lengthof(g_unblocked_nsvcs_sig); j := j+1) {
-				if (g_unblocked_nsvcs_sig[j] != i) {
-					new_unblocked_nsvcs_sig := new_unblocked_nsvcs_sig & {j};
-				}
-			}
-			g_unblocked_nsvcs_sig := new_unblocked_nsvcs_sig;
-
-			var Osmocom_Types.ro_integer new_unblocked_nsvcs_data := {};
-			for (var integer j := 0; j < lengthof(g_unblocked_nsvcs_data); j := j+1) {
-				if (g_unblocked_nsvcs_data[j] != i) {
-					new_unblocked_nsvcs_data := new_unblocked_nsvcs_data & {j};
-				}
-			}
-			g_unblocked_nsvcs_data := new_unblocked_nsvcs_data;
-
+			ro_integer_del(g_unblocked_nsvcs_sig, i);
+			ro_integer_del(g_unblocked_nsvcs_data, i);
 		}
 		g_nsvcs[i].state := state;
 	}
diff --git a/library/Osmocom_Types.ttcn b/library/Osmocom_Types.ttcn
index 06920bf..23f8fd9 100644
--- a/library/Osmocom_Types.ttcn
+++ b/library/Osmocom_Types.ttcn
@@ -294,6 +294,25 @@
 	return false;
 }
 
+function ro_integer_add_unique(inout ro_integer roi, integer new_entry)
+{
+	if (ro_integer_contains(roi, new_entry)) {
+		return;
+	}
+	roi := roi & {new_entry};
+}
+
+function ro_integer_del(inout ro_integer roi, integer del_entry)
+{
+	var ro_integer tmp := {};
+	for (var integer j := 0; j < lengthof(roi); j := j+1) {
+		if (roi[j] != del_entry) {
+			tmp := tmp & { roi[j] };
+		}
+	}
+	roi := tmp;
+}
+
 type record of ro_integer roro_integer;