Is it possible to break users into groups and send them to each modem?

Question

Computer networks

I have 4 modems, 1 mikrotik (router).
How to split users into groups (4 groups) and send each group to each modem.

Answer 1

On a tick, you make four different srcnats and four adresslists, in the address lists you specify IP computers or subnets, in each srcnat in the "src address list" select the desired address list.

Answer 2

4 different SRC-NAT by address-lists. In the address list just groups of users.
In src-nat in interface/out interface, no
action is needed in these rules, and so src-nat
That's what else you need to do next - mark these packets with a label. For each src-nat rule on the same packets, you need to put a label, like, src1 - src4
And indicate in the routing table that we have 4 default gateways, each of which belongs to a specific label.