DVD sound through car stereo?

I recently bought a brand new Honda CRV off the showroom floor for a steal! It had every upgrade imaginable since they needed to get the 2004 model on the SR floor. It has the DVD upgrade package in it and I am wondering if it is possible to run the sound throught the stereo system instead of just the wireless headphones. This way everyone can hear it since it only comes with 2 wireless headphones that my son won't yet wear since he is only 2 1/2. Anyone have this knowledge??? Thanx and take care!

DAVE