nostr:nprofile1qy2hwumn8ghj7un9d3shjtnyd968gmewwp6kyqpqncj290mmvqyju84pk2ammz8x02rugl97dl9wp5nsv425uk57jtxqvshgtw group-calls are not around the corner, unfortunately. So for now, you can for example use a browser-based video call solution and post a link to the group chat.