According to reports, it seems that users have spotted that group FaceTime is now back and was spotted in macOS 10.14.1’s public beta. This doesn’t necessarily mean that the feature will make it in the next update to macOS, but the fact that Apple has put the feature back means that they might have ironed out whatever kinks that could have potentially hindered its release.
It should also be noted that group FaceTime has also returned in iOS 12.1 which is also in beta, so hopefully the feature will be available when either of these two updates are released to the public. That being said, those who are interested in checking out the beta can do so as Apple has made them available to the public.
However given that this is a beta build of macOS 10.14.1, there is a chance that there might still be some bugs that haven’t been addressed, so maybe it’s not the best idea to use it as your daily driver for now.