[syslinux] change SERIAL baudrate as-needed?

[Steve Rikli]

I've got a working PXELINUX 6.03 setup (which started as 3.08 way back in
the old days :-) ), with this definition in the top-level default menu:

SERIAL 0 9600

This has been fine for years, but recently we've added a new pool of
systems which we need to run at 115200 on their serial consoles.

I can't change the default 9600 (still lots of systems running and
getting installed that way), so I'm wondering:  can I simply re-define

SERIAL 0 115200

in some sub-menu for the appropriate pool of systems?  I haven't simply
tried it yet since I'll need to reconfigure terminal server ports, so
I thought I'd check to see if anyone else does something like this
before I try it.

Cheers,
sr.