BTW, there is a uservoice for having multiple invite groups. So you could have a Clan one, people who play RT, a list of diplomacy players, etc. I think this would fall under that existing uservoice item, so you may want to vote on that one:http://warlight.uservoice.com/forums/77051-warlight-features/suggestions/1142113-add-a-friends-list-subset-to-the-invite-list
BTW, it is 5 years old last month, and has the 4th most votes on uservoice. Not sure why this has never been implemented (I would hope it has been worked on recently). I just looked at the top dozen or so ideas and it is the only one Fizzer did not say "was not on the immediate road map". So it clearly isn't something he sees issues with (difficulty, popularity vs cost).
Edited 11/5/2015 18:40:40