Yes, using a custom hidden window is what I do in a somewhat related situation. I would create 3 custom windows, one for each of the networks. Use them as FIFO buffers by using /aline to add all text from the associated network. Set a timer for each window to read line 1, output to the server, and then delete it from the window.
BTW, server flood control can be set to anything the server ops want, but I don't believe 1 line every 1 sec will work for you.