This CodeLet let you Programmatically manage members of sub groups. also you can add sub group.
you can inviter/remove peoples of sub groups. Invitation will be sent by email.
after installation of this CodeLet you must have to pass the group gid on query string,
1-Organic groups ( og )
2-Subgroups for Organic groups ( og_subgroups )
3-OG Invite People ( og_invite_people ).