Merge lists#635

Hello. It would be helpful for us if we could have a way to merge multiple shared lists into one automatically, but that would still remain dynamic (even if read only).

Example: I have a Annie and Robin sharing their lists with me. I’d like to merge them into one list regrouping all their current tasks automatically.

This would allow for creating different “categories” of lists (groups and subgroups) and have a better overview for large groups