[Samba] Samba4 and VPN browsing / accessing !

[Computer service SPb.]

There is router/vpn server with 2 static NICs - Lan (local area network) ,
and Wan (wide area network) .
Also pptpd/xl2tp, iptables is installed at router.
Forwarding, proxyarp and broadcast relay is set up at router.
Samba4 4.1.x is installed at router. There is no any Wins in Lan.
So, there are Ran (remote access network) clients (client-to-server) being
conneted by pptp/l2tp using broadband/cellular connections to the router.
Win XP/7 are as Lan/Ran clients.
There are 2 NetBios groups in Lan, one is the same as Samba4 group, second
is not.
Ran users has its own groups, who what, for example MSHOME, WIND-35, ART
and so on, some Ran users has groups the same as Lan users in.
At the moment NetBios access by name works even without Wins server for
both direction: Lan->Ran and Ran->Lan and Lan/Ran -> Router, Router ->
Lan/Ran.
But trouble is in visibility of Lan clinent in neitwork neighborhood of Ran
clients and vise versa.
At the moment I tested Win XP as Ran client only.
And have reached for this time the following:
Lan users can see Ran users in Lan' s neighborhood as Ran users can see Lan
users in Ran' s neighborhood if Ran user group is the same as one of Lan
group (name is the same) , for example:
Lan groups: WORK and MSHOME, if Ran user who has connected to VPN sever has
its group named WORK or MSHOME he/she will be able to see Lan users in
his/her neighborhood as he/she will be visible for Lan clients in its
environment.
But if Ran user has its group named different from Lan groups nobody will
see each other,
for example, Ran users group is WINDOW-23F, he/she will not see Lan users
as they will not see this Ran client.

The question is how to make that all either Lan or Ran clients could see
each other independently from its groups name ?