diff --git a/local.tf b/local.tf
index 6c3249d..58a59cb 100644
--- a/local.tf
+++ b/local.tf
@@ -1,7 +1,9 @@
 locals {
   asg_tags                  = ["${null_resource.tags_as_list_of_maps.*.triggers}"]
-  cluster_security_group_id = "${var.cluster_security_group_id == "" ? aws_security_group.cluster.id : var.cluster_security_group_id}"
-  worker_security_group_id  = "${var.worker_security_group_id == "" ? aws_security_group.workers.id : var.worker_security_group_id}"
+
+  # Followed recommendation http://67bricks.com/blog/?p=85 to workaround terraform not supporting short circut evaluation
+  cluster_security_group_id = "${coalesce(join("", aws_security_group.cluster.*.id), var.cluster_security_group_id)}"
+  worker_security_group_id  = "${coalesce(join("", aws_security_group.workers.*.id), var.cluster_security_group_id)}"
   workstation_external_cidr = "${chomp(data.http.workstation_external_ip.body)}/32"
 
   # Mapping from the node type that we selected and the max number of pods that it can run