You'll have to describe the functionality and settings of each individual device:
- do they perform firewalling?
- what are their WAN and LAN IP addresses?
- do they perform NAT?
- what kind of connectivity between subnets do you need, full (almost transparent) or just for a few select services?
- And perhaps the most important one: do you require two distinct subnets?
Here is situation how it is, it evolved for 8 years.
First was 192.168.240.0/24 net running OPG RTG + imaging system on 2 PC with just 1GBit switch. With Dongle only possibility to place PC on device was necessary to ad wifi so CRS109 was added WIFI + 1Gbit ports (there are other limitations OPG direct to router, cable no longer than 2m etc... ),
Second network payment terminal was made. Its own network 192.168.3.0/24. no big deal LTE router placed on spot with best 4G signal, connected via passthrough powerline to terminal + airprint + payment registration on government site via iPhone (easiest app).
Third network CAD CAM system was installed. CAD/CAM needs internet access. Now law mandate us to get PCs in 192.1687.240.0/24 online. So far so good.
There are just basic settings on Mikrotik routers, when you make quick settings Home AP point.
I have to self study everything. Nobody helps. Not sure if company installing first network it still exists, others just cares about their networks if any. That is why I looks easiest but correct solutions.
If necessary I completely made setup of routers, but initially i need to help and know what I am doing.
There is small perk. On x.x.240.x network is NAS for backups. So I would like to backup all PCs to this NAS + ESET end point security has possibility to centrally manage software on all PC
That is my second target. On 192.168.240.x network is also RVG RTG device with drivers for win98 I was able to convince to work on Win7 but not on Win10 so Win7 is essential there too.
Two subnets are there due to traffic ..240...OPG to imaging server, vista + OPG to imaging PCs + to wifi, ..230... CAM to CNC data, CAD to CAM. If one of them is not working second one must be.