How to implement the execution of a bash script on a software router through one of the two available Internet channels?

Question

linux

There is a router with installed ClearOS (read CentOS). The machine is engaged in routing 3 channels of Internet access.
But on the router, it is necessary from time to time to synchronize with a remote server and download data from it to the router.
Tell me how to implement the execution of a bash script through, say, the 3rd available channel on the router?

Answer 1

to force to go to a remote server through the 3rd channel?