Merging Sequences Between Two Semisynchronized Lists

Question

I was faced with an interesting problem, and I wanted to know if anyone else had addressed this situation before I would conduct theoretical studies of the days.

I have 2 systems. The first system maintains a sorted list of data. Suppose he has a list of named actions. The user of this system can manually order them at any time.

System 2 creates this list in itself when creating a new project. It also syncs with the source list. A user in system 2 can create user actions. They do not sync with the original. System 2 stores a list of systems 1 and customs in a table. System 2 user can resequence / manually sort this list.

Now this is the hard part. If users of system 1 reorder some of these actions, we want them to reorder in System 2. We want these specific elements to reorder, but not reorder, elements that have already been changed by the system user.

i.e. System 2 users reorder several activities. The System 1 user reorders these and other actions. This will only affect those that the user of system 2 has not changed.

I could make it more difficult in my head than it really is. It definitely sounds like an interesting puzzle.