How to set up permissions for a specific user to access a specific branch in firebase realtime database?

Question

React

All the best!
Please tell me, let's say there is such a structure



And let's say there are registered users (Authentication - Users):
[email protected] , [email protected] , [email protected]
And you need to specify something in the database rules that user1 has @mail.com had read/write permissions only to the dataMass1 branch , [email protected] only had dataMass2 and [email protected] respectively only dataMass3

Applications will be implemented on React.

P.S. it is also planned to create such rules when registering a user, well, I will probably do this through the firebase cloud function, now at least understand how the access control rules should look