Just as easy as it sounds. It would be nice to have player groups feature save your lists, and automatically add you back to the group you have been before, if your friend joins the game. I have to say, the groups being temporary is probably one of the most important reasons for why I am not using this feature much. Of course you could also still keep temporary version of player groups and maybe let players choose if they want temporary or permanent groups in game settings, each for their own, something like this. Now, sorry for posting this in generic suggestions category - I just don’t think it fits anywhere else, but if it does, please let me know, or just move the topic to the right category.
A bump of my old thread. A whole year later, I still believe this could be really useful feature, though still a minor change. If it has been implemented already I might have had missed out on it as I haven’t been playing Tower in a while. If not however, I welcome further discussions.