Filter traffic on Mikrotik or on a remote router?

Question

Mikrotik

All the best!
Colleagues, something went into a stupor when setting up Filter Rules on Mikrotik.
The situation is as follows:
There is a Mikrotik, an l2tp + IPSEC server (at the office) is raised on it, there are remote clients. Everything works great. Recently, several users have to work from one office, and we have encountered a problem with their network, only 1 user can work remotely. At connection of the second on VPN to office, connection of the first falls off. We installed a router and set up an L2tp Client connection on it. All users now have access to office resources.
My question is this. How can I give access to only a few hosts on the office network from a remote network? I would like to understand whether it is possible to do this on Mikrotik in the central office.
PS all network interfaces are united in bridge (except for the first WAN).

Answer 1

Thanks to all! After watching this video clip, I understood how to set up filtering. I
give the link below
https://www.youtube.com/watch?v=3ESRncrnCM4
Thanks again to everyone!

Answer 2

Decisions are made by the one who is in charge :)
Therefore, it is necessary to filter where to let users from the branch on the central mikrotik. I don’t know how this is done in L2TP, but in pure IPSec, packets go through Filter twice and I filter them on the second pass, when they are already decrypted.