XF 1.4 Modify registered memberlist to display members of a set user group or create something similar


I am looking to change the Registered member list or something similar to display all members of a set User Group.
Also I would like to display a couple of custom fields on the list.
I am using XF 1.4.9.

How would I got about this, or if you could point me in the right direction that be great.