To enumerate groups and their membership you will have to:
1) bind to the computer
$Computer = GetObject(WinNT://$Domain/$Computer,computer")
2) Filter for groups objects
$Computer.Filter = "group",""
3) enumerate groups
Foreach $group in $Computer
4) get membership
$Members = $group.Members
5) enumerate members
For each $member in $Members
6) print
$member.Name
