Basicly my idea is a system where you have a group that you create and invite people into, and once in the group it stores separate a leader board where you compete with friends/people you invited instead of everyone. Because lets be serious, not every one is the best at this game(me). Yet we all want to feel competitive even if we can't keep up with the pros. Also when I say new leader board, like it would add more to the list that pops up when you finish a song, and if you had more than enough groups to make the list too long for the screen it simply can scroll down.
Most likely not the best thought out idea, nor the most important thing needing work on. Just something I myself think would be cool to see in the future.
Update: Just thought of something else that would be cool to add to this, maybe some groups could filter which modes that were used. For example if you want only people that play easy mode to get ranked on this group, you could do that. Same with hidden or multiple modes.
Most likely not the best thought out idea, nor the most important thing needing work on. Just something I myself think would be cool to see in the future.
Update: Just thought of something else that would be cool to add to this, maybe some groups could filter which modes that were used. For example if you want only people that play easy mode to get ranked on this group, you could do that. Same with hidden or multiple modes.