virtual serial port setting

I noticed that in FS-UAE, when you put a serial_port setting into one of the machine configs under FS-UAE/Configurations/, it gets moved automatically into your global Settings.ini for the whole emulator. Or at least that's what happened on my setup: I put "serial_port = /dev/tnt2" (a virtual nullmodem device I have setup on my system) into FS-UAE/Configurations/A3000.fs-uae, and it magically got moved into my emulator-wide Settings.ini.

The reason I'd like it to stay specific to a particular machine configuration is because I'd like to be able to easily change where my virtual serial device is pointing. Sometimes I'm using the serial port for telnet BBS's, by pointing it at tcpser on the host Linux system underneath via the aforementioned nullmodem device. Other times, I'm pointing it at /dev/snd/midiC4D1, to use Amiga sequencing programs with real MIDI equipment.

Is there a convenient way to switch this back and forth? I suppose one way would be to put the serial_port option on the command line when running FS-UAE, but that's not as easy as having the launcher do it with stored machine configs. (Yes, I know, I've been spoiled by FS-UAE's nice GUI launcher...)

BTW, thanks to Frode and the devs for the serial_port option. I get the impression from the docs and forum messages I've read that it was only intended for debugging purposes and maybe getting a remote Amiga shell, but it's actually useful for all kinds of things.