Thanks. This all pretty much worked. I went with the --config option.
There is an anomaly I had to work through.
On linuxA, I have four separate instances of rslsync running each sharing a single folder. On macB I have one instance, the Resilio Sync application connected to four shared folders. At first I tried to "Use predefined hosts" on macB. For each shared directory, specifying linuxA:port, where there are four different open ports, one for each instance.
For whatever reason, this would allow only one active peer connection at a time. I had to kill 3 of 4 processes on linuxA to get the desired one to connect. Each of the four worked by itself. But not more than one at a time would connect.
For the time being, I have switched to using Tracker Server, and all four work at once. Yay. I would just prefer to not use Tracker.