Hello community, today I am writing to request your collaboration.

I have a network with 3 subnets: I exemplify below
IP PUBLIC Service - 12.116.188.0/24
  Server 1a: 12,116,188.41

Network B - 192.168.11.0/24
  router 1b: 192.168.11.1 MIKROTIK RB2011
  Computer 2b: 192.168.11.194

Network C - 192.168.0.0/24
  router 1c: 192.168.0.6 Mikrotik RB1100

Network D - 192.168.50.0/24
  1d router: 192.168.50.1 MIKROTIK RB2011
  2d router: 192.168.50.11 CISCO 8000

And I need the computer 2b to be able to connect to a server 1a with ip 12.116.188.41 which is only accessible by means of a vpn that is established in the subnet 192.168.50.0/24 in the router 2d.
My question is how I could do to carry out what I need.
I thought I would use package marking, connection marking. But I can not make it work. They could guide me a little more or tell me the best method to do what I need.

  Thank you very much community !.