Everyone will receive the same login screen. You would use a OnFirstWindowOpen ScriptTrigger to run a script to test for which user is logged in and direct the user to a layout. Get(AccountName) to determine which user has logged in.
Get ( AccountName ) is good for identifying a specific user. In some cases, you can use Get ( accountPrivilegeSetName ) to identify groups of users.
I thought somewhere I had seen in the URL a -Layout=, or some such.