MIDI: Automatic accent on notes starting bars

[Lukas-Fabian Moser]

Folks,

is there a way of automagically adding some volume increase ("accent") 
in MIDI output to any note that happens to start on the first beat in a bar?

It seems a well-defined enough request to me so that it should be 
perfectly possible to do this in scheme, but I'm afraid this exceeds my 
very limited LilyPond-scheme abilites...

Slight complication (maybe): In my scores, the metre changes all the 
time, so one really would have to use the actual timing of a note.

Lukas