Freestyle across different mapsets of similar total time

[hlysine]

Freestyle is an awesome way to bring friends together even if we play different modes, but it is really limiting having to pick maps with difficulties for multiple game modes. We often run into this awkward situation where we have the same song in mind, but mapsets for this song are separated by game mode, so we either have to play converts or play an unfamiliar game mode.

An extreme example is this:
https://osu.ppy.sh/beatmapsets/1079354#osu/2258242
https://osu.ppy.sh/beatmapsets/1275044#taiko/2649299
These two maps have the same track, so ideally as a standard player, I should be able to play this with a friend who picks the taiko version. But since freestyle forces everyone to pick the same mapset, the only solution right now is to pick the standard map and have the taiko player play convert, which severely degrades the experience.

My proposal is to allow each player to pick any mapsets with a similar total duration as the one listed in a multi room when freestyle is on. If necessary, the game can compare metadata (author, title, etc) to make sure the mapsets are related.