one of the documented procedures in this installation of the ACS
edu_get_roles_for_group   db   group_id
What it does:
returns a list of list of roles for a group_id and their corresponding pretty names in the form of {{role1 pretty_role1} {role2 pretty_role2} ...}
Defined in: /web/philip/tcl/education.tcl

Source code:

    set selection [ns_db select $db "
    select unique r.role, pretty_role, sort_key 
    from user_group_roles r, edu_role_pretty_role_map m
    where r.group_id=$group_id
    and r.role=m.role 
    order by m.sort_key"]

    set role_list [list]

    while {[ns_db getrow $db $selection]} {
	lappend role_list [list $role $pretty_role]

    return $role_list