Add invite code for existing logged in network user?

Hello,

I have 2 questions regarding the Membership plugin.

1. I was wondering if its possible to have an existing network user be required to enter an invite code if “Require Invite Codes” is checked in the ‘Membership > Extras’ settings?

2. I might be missing something here but when an existing network user registers for a site, that user is not seen under ‘Membership > All Members’ or the ‘Users’ tab.

(ex. UserA registers for membership at test.com/sitea, but then also wants to register to test.com/siteb. UserA registers on test.com/siteb and is given access to view content (hopefully after submitting the invite code–see question 1 above), however UserA is not seen in ‘Membership > All Members’ or the ‘Users’ tab of test.com/siteb.

Thanks!