Subject may be vague but let me explain.
I have two content types
 car content which holds some cck fields that carry data for a specific trim of a car: for example an (X5) trim of the BMW car, that content type has cck fields like (rim size, seat material...etc).
 listing content type has the same (rim size, seat material) cck fields along with other cck fields that doesn't exist in the "car" content type, and has also a "Trim" cck field which is a select list.
What I want to do is when selecting "X5" trim, all common cck fields (rim size, seat material) among the two content types will be auto populated or auto filled with values from the "car" content type.
Is this possible? please point me to the right direction, I have been searching forever without an answer.