How to get a client ID?

So we are creating an app using jetadmin, which has several clients say client1, client2 etc.
Each client has several users, say client1user1, client1user2 etc for client1 and client2user1, client2user2 etc for client 2.
Each user within a client sees the dashboard powered by the same folder within an s3 bucket.
So, if there is a user in client1, we want to obtain the name of the client for this user i.e. the client ID, so that all the data is read from within the folder dedicated for the client1.
In jetadmin, we were able to get user specific information, but how do we get client specific ID like this ??

I hope my question is clear, please let me know if anymore information is needed.