What is a camel?
A horse designed by a committee.
The problem is that your client is not aware of the conflicts that happen in these situations.
A common practice is to give 3 revisions and then the hourly rate kicks in. This is marked clearly on the contract.
I worked around a miltiple client problem once by building a small website and posting the video on it for them to view.
I was working in Baku, Azerbaijan and the clients were in Rome, Italy.
It was important that one person was designated by them to collect all the thoughts and ideas for change and them channel them to me by email cc’d to the group.
This stopped duplication and minimized conflict.
But.
There is a limit to this and at some point you have to take charge of the edit or it just goes on forever.
Clients appreciate a strong opinion if it is presenteds in a positive way.
Best of luck.
Vladimir