[Samba] Samba4 and Lan/ Vpn clients browsing / accessing !

[Computer service SPb.]

 There is router/vpn server at Ubuntu 12.04 LTS 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, that is Vpn) 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 (second is without any servers) .
 Ran users has its own groups, who what, for example HOGROUP, WIND-35, ART
and so on, which differ from Lan groups, some Ran users has groups the same
as Lan users in, for example MSHOME.
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 clinents 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 BUT if Ran user group is the same as one of
Lan groups (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 ?
 I suppose at the moment that some packets (and some broadcast as well) is
not reached router or other subnet. Because of as Lan as Vpn are actually
two different subnets and at the same time prxoyarp is on and common
addressing space is involved.
But I am not sure if quesiotn is in arp/route values or in Samba4 settings.