Please keep the mailing list in copy.
You mean that i should perform the npt or another integrator to the
"particles" and then compute the temperature and pressure and after use the
fix_modify?
1. I don't understand your question.
2. you don't give enough information on your problem: why can't you
simply integrate group all?
3. please really take the time to read thoroughly the following pages:
You have to define a compute temp that computes the temperature of
group particules, and assign it to your fix nvt through the fix_modify
command. The order doesn't matter.
Best,
Laurent