Hi Yusuf,
I am not entirely sure what you specific use case is, but is see some options.
You could use nonpersistable entities: they exist only in the client, so users will not see each others nonpersistables.
Another option is to use entity access. If you enable “store owner” in the properties of a persistable entity:
Then in the entity access rules of that entity you can do:
Now the user can only see the objects that were created by the user.
For more info see https://docs.mendix.com/refguide/access-rules/#xpath-constraint
Would one of these options work for you?