Google's upgrade strategy for Duo could include some highly sought-after features. Android Police sources say Google is testing a group calling feature in at least the Android version of its video chat app. It only supports seven people at once (no 32-person parties here), but it's relatively straightforward. You just have to create a group and then start a call with those people. If there's a limitation, it's that you can't add anyone into a group in mid-call.