Typically used when you have like lots of users / devices behind a NAT to prevent running out of port numbers (PAT) for a single IP NAT but not typically for 100 users/devices, never tested, but maybe:
There a wiki for that https://wiki.mikrotik.com/wiki/Manual:I ... :1_mapping
Not really the same thing, the wiki is for 1:1, and use "netmap" as action
The intention of my example is that the router has a pool of IP's to NAT to, i.e. I have seen it once on a Fortinet device where we had +- 4000 mobile clients NAT/PAT out on a single IP, it complaint about available ports and I had to specify a pool of IP's for NAT/PAT.