Thanks Franck, I stay on matrix, here my patch. I hope you could understand.
http://giair.music.free.fr/patchs/partage/routing/
your system with $1 and $2 and select object to pass the message, it's very clear ! It could be a solution.
but I would control the routing (mapping ? could we say that ?) with a simple message, so I am gone through another direction.
I think my patch is too big for this action. I will try with your solution. It's may be more comfortable. Because if I have to change the "y" paramaters in mine, it's a true headhacke !
best
JR