Dual WAN Router Setup

I’m new to MikroTik devices and weak with routing in general. I need to setup the following in RouterOS:

Goal being that A Corp and B Corp can request data through their Cell’s and the WAN ports on the router to 192.168.0.0/24 and the router will pass those packets on to the RTU’s.

I’ve segregated the router ETH1 and ETH2 ports as WAN and addressed them, as well as assigned the Bridge it’s IP. What type of rules am I looking at to accomplish the routing I’m looking for? Thanks!

I guess I would suggest that we get rid of the port forwarding and set up a VPN server to make sure the connection is secure and to encrypt the packets going through, all that would be required is to have a public IP address on one side and it does not need to be static as we can use Mikrotiks DDNS service or if we do not have that we would need to use zeroteir or maybe set up a CHR in the cloud to act as a VPN server between the two sites.

From there it is simple as setting some routes but where and what will be dependent on how we can set this up so let us know what you think of this before suggesting anything further?