You don't have to worry about teams as you cannot have an empty team.
I've not tried to get a members list for Groups or Companies and members are not listed as collections in the API. Maybe @Doug_Den_Hoed__AtAppStore or @skyehansen or maybe @William-- may know how to get to members from the group or Company object.
From the user object, it's here:
displayname=All Groups
listdelimiter=
listmethod=nested(userGroups).lists
namekey=group.plural
textmode=true
type=iterate
valuefield=group:name
valueformat=HTML