Opening the Part/Modeling file in Simulation?

[hydronicengr]

I'm pretty new to NX so excuse the newbie question. I'm using NX 8 and whenever I open up a simulation file (.sim), it opens up the sim and fem file perfectly, but does not open up the .prt file where the model is located. I would like to open this file up to make some changes to the model.

Is it possible to open up the .prt model while having the sim or fem open?

Thanks!