The profile is something I didn't consider. Since in the only way I can see it working, the "master" mapper still owns the map and updates it, they couldn't count towards things like your Mapper Ranking and such, or else you'd have the same map counting for multiple mappers.
A new subsection under Beatmaps in the profile, titled "Beatmap Collaborations," which would inversely lookup all maps with difficulties authored by you, would achieve this in the most sensible way. (It could be cached to spare the database.)
A new subsection under Beatmaps in the profile, titled "Beatmap Collaborations," which would inversely lookup all maps with difficulties authored by you, would achieve this in the most sensible way. (It could be cached to spare the database.)