Automatically Assign Wordpress User Role to Memberships Plugin

I want to automatically assign custom wordpress user role to memberships "group".

For instance "Year 1" membership group (created @ http://example.com/wp-admin/admin.php?page=membership2) should automatically populate with users that have the custom wordpress role "subscriber" (or if I want to make custom roles ie. "subscriber 2015")

How can I do this?