Hey eetmorsqrls. I see you on RTP at the moment 
I like 1v1's but I also like 2v2 or 3v3. But usually its hard to get a balanced good game more people there is. So I like to play with less.
In your case if I ever invited you, you just say not into 1v1's buddy, and then I will be aware so next time when I want to play a 1v1 I won't invite you. However if I want to play a 2v2 or more then I will.
Another feature I just thought about is having your own RTP page where you can state such prefences. It can be like your homepage for others to read. In your case eetmorsqrls, it can say not into 1v1 >.< lol
Player can state what and how they like to play games. Maybe say when they will be online if others wish to meet and play. Also there should be stats to show which games players play and how long they spend playing them like on steam. This will give a good indication to someone looking to invite whether to bother or not.
Right now people like my self shoot off invites knowing nother about people and get no results.
I hope that's helpful to the developers 