Subscription - how to extend "add user" to "add multiple users"?

[kafi]

In the admincp I am able to add user to subscription. However I wish to add more than one user with form (without repeating the proces ).

Currently there is option to add one user (user1) per submit, I need to add multiple users per submit (user1, user2, user3).

In this form:
Attachment 69627


Any help with the code change would be more than appreciated

Thank you!