Is there are URL scheme available to WatchOS that will start a group call?
The facetime-group prefix prompts the user to start on iOS, but is unsupported on watchOS. Additionally, on WatchOS, the user can manually select contacts to add to an existing facetime audio call.
URL scheme example that worked on iOS: facetime-group://?remoteMembers=+12345678901;+23456789012&isVideoEnabled=1
Console warning when attempting on WatchOS: -[SPApplicationDelegate extensionConnection:openSystemURL:]:2418: URL with scheme "facetime-group" not supported.