diff --git a/custom/data.vpc.tf b/custom/data.vpc.tf
index f7ccfd8..7ac993a 100644
--- a/custom/data.vpc.tf
+++ b/custom/data.vpc.tf
@@ -6,13 +6,13 @@ data "aws_vpc" "this_vpc" {
 data "aws_security_group" "ingress_security_groups" {
   #  count = length(var.ingress_security_groups)
   #  id    = element(var.ingress_security_groups, count.index)
-  for_each = [for sg in var.ingress_security_groups : sg if !strcontains(sg, "/")]
+  for_each = toset([for sg in var.ingress_security_groups : sg if !strcontains(sg, "/")])
   id       = each.key
 }
 
 data "aws_security_group" "egress_security_groups" {
   #  count = length(var.egress_security_groups)
   #  id    = element(var.egress_security_groups, count.index)
-  for_each = [for sg in var.egress_security_groups : sg if !strcontains(sg, "/")]
+  for_each = toset([for sg in var.egress_security_groups : sg if !strcontains(sg, "/")])
   id       = each.key
 }