Hm. This looks like a problem I had with a family schedule that had to accomodate changing work shifts and several grandchildrens' school dates.
My amateurish result can be seen at
http:www.oceandreams.net/fam_sched/
using a text file as a database.
I'll e-mail the code if it's at all usefull to you; I can't do it from work, otherwise I'd attach it here.

Regards,
Clachair