Hello Hoodognik,
Maybe I haven't undestood well what you need, but to have a list of users in a particular group, you need to create a Select Dynamic, with the following settings:
SQL Query:
SELECT u1.name as text, u1.id as value FROM `#__users` as u1 LEFT JOIN `#__user_usergroup_map` AS u2 ON u2.user_id = u1.id WHERE u2.group_id = 2
P.S. I haven't specified the storage, since I do not know what exactly you need and where.
Regards,
Aleksandar