We have a new home built in 2001 and unfortunately we want to change a couple of major framing possibilities.

We have a living room that is approx. 14' x 16' with an 18ft. ceiling. This height also extends into the foyer. I have two walls on each side of the living room and I want to design a loft 4-6' wide x the width of the living room (14 feet).
My question is actuallly pertaining to the structual integrity of the loft and the ability of the walls on each side of the loft to handle the load. Now these two walls are currently running parallel to my open web floor trusses (16") 24" oc. with a span of approx. 18 ft. therefore the loft would run perpendicular to the floor trusses.
Now..one of the walls to which the loft would secure to is a 2x6 and the other is 2x4.
Do I need to build a load center underneath both of these bearing walls to support a loft, or is it possible to strengthen them with a beam or is it totally unnecessary?