ok i got it .
Now i use something like that :

material model1name_mdl
{
effect="my_effect.fx";
}
material model2name_mdl
{
effect="my_effect.fx";
}
material modelXname_mdl
{
effect="my_effect.fx";
}
etc..etc..

Thats the fastest way i found for the moment.
Thanks for your answers.

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