diff --git a/modules/colossussspBidAdapter.js b/modules/colossussspBidAdapter.js
index b1d36d1095c..72df7c7b465 100644
--- a/modules/colossussspBidAdapter.js
+++ b/modules/colossussspBidAdapter.js
@@ -47,7 +47,10 @@ export const spec = {
    * @return boolean True if this is a valid bid, and false otherwise.
    */
   isBidRequestValid: (bid) => {
-    return Boolean(bid.bidId && bid.params && !isNaN(bid.params.placement_id));
+    const validPlacamentId = bid.params && !isNaN(bid.params.placement_id);
+    const validGroupId = bid.params && !isNaN(bid.params.group_id);
+
+    return Boolean(bid.bidId && (validPlacamentId || validGroupId));
   },
 
   /**
diff --git a/test/spec/modules/colossussspBidAdapter_spec.js b/test/spec/modules/colossussspBidAdapter_spec.js
index e453bcbc997..91f900d6279 100644
--- a/test/spec/modules/colossussspBidAdapter_spec.js
+++ b/test/spec/modules/colossussspBidAdapter_spec.js
@@ -61,6 +61,7 @@ describe('ColossussspAdapter', function () {
     });
     it('Should return false when placement_id is not a number', function () {
       bid.params.placement_id = 'aaa';
+      delete bid.params.group_id;
       expect(spec.isBidRequestValid(bid)).to.be.false;
     });
   });