Memberships 2 how to disable payment

Is there a way to disable payment in the Memberships plugin?
I plan to get payment trough liceces ouside of the site. (company pays licence, and usesr use the site without having to deal with payments)
What I am looking for is a setting where all memberships can be picked by the user without going to checkout.
My main reason for using the plugin is the shortcode that hides and shows content based on group membership. Do have to go into the code and modify the payment gatway or is there other options?