This suggestion has appeared lots of times before!
Here's a list of threads:
Suggestion: Co-owns!!
Suggestion - Co-owning feature
Suggestion: Co-Own
Co-Owning Feature?
co-owning with other users
Co-Owning characters?
{SUGGESTION} Collabs and Co-owns
Co-owning characters?
Co-own option
Minsu has replied to several of the threads and a few of them are quite popular, so the admins probably know of this feature and are considering it!