Record Level Access Control by Group - any better approach?

Record level access control by group is not supported by default, and I am looking for any way to achieve it by combining various features of ZC.

When "userA" add a record, it is accessible only by him by adding a criteria like this.

Added User equals to zoho.loginuser

The same thing applies to "userB", "userC" and "userD".

Now, "userX" is a supervisor of "userA", "userB", "userC" and "userD". I want to allow userX to access 4 users' records.

My idea is to create one field, called "Permission" field. I am going to put "userX" in their records.

Then, I add a new criteria:

Permission filed contains zoho.loginuser

I think userX can see 4 users' records now. But, this method requires the admin to add "userX' in the "Permission" field manually every time they create a new record.

Here, I am thinking of creating a workflow withe schedule. I have not tested it yet, but would this concept work?

Update "Permission" field to "userX" if "Added user" equals to "userA", "userB", "userC" or "userD", and the schedule is every day.

If there is any way to fill out the "Permission" filed automatically based on users, that would be better. But if we have another supervisor, such as userY who should be able to access userF, userG, userH, and userI, I could not find a way to fill out the Permission field correctly.

Instead of adding "Permission" filed, dose lookup up field work? I can create another table just for users relationship. If the lookup filed show "userX" from the other table based on the zoho.loginuser, that will allow all new records to have "userX" automatically. Can anybody confirm if my idea about look up work like that?

I want to reduce admin's involvement as much as we can.

If somebody has totally different idea, and it is much better and is ready working, I would like to have advices.

Thank you very much.