I've got an older Garmin 126 that's serving me well, but it's old
non-mapping so I'm considering upgrading soon. One feature I think
would be very useful is to be able to set a different audible alarm,
other than the standard arrival beep, when I get close to a waypoint
that I've marked as a shipwreck or obstruction. Can any units do
this?

Thanks, -JZ