[maxmsp] detonate infos

Hello,

I'm trying to use 2 detonate objects to chain midifiles. So i need to  
know when one of these finished playing its song to start the other one.
It's really easy to get such kind of message in Max window, but i was  
unable to get it inside my patch to tranmit the information from one  
detonate to the other.

Any idea?

Thanks,

François Parra.