I have an application XYZ, under which I have 3 development branches. 3 Developers are working on their respective user stories and each developer have their own branch. Our requirement is to make sure that one developer shouldn't see the changes implemented by other 2 developers (2 branches).
So, I created a toggle and enabled it to - Only myself: OperatorID.
Even then, Other users are able to see the changes I have done.
While I haven't explicitly tried it, I'm not sure if individual branches can support restriction to a specific operator. The below help file discusses the use of "Team Applications" to this type of branched development: