Depending on the provider, this is a general load balancing -> if one gateway fails, the second one is used. If you want to split the data traffic, you have to mark the connections (point: "Firewall marking"). You can also use the bonding:
https://wiki.mikrotik.com/wiki...
Connects 2 interfaces to a single link. This allows load balancing and failover.
We apologise for the extremely late reply.
