I agree with LatsMac, upper and lower body split.
Traps allow support and function for the shoulder girdle and the upper back. (warning...I'm going to use that overworked word again) It is a "Core" unit just like the ab/lower back are. If you were in a lab and had a numbing element injected into the total trap area, than you would have a very hard time doing any overhead presses, let alone any form of DB raises about and above shoulder height. Your DL and any pulling movement (cleans, Hi-Pulls, etc) would suffer also. Even the squat (bar on the trap/neck area) gets into the act.
Anyone can work the traps with the shoulders or back for successful results. Personal view is to work the traps with the back. Because the traps are a very powerful short ranged muscle group and capable of handling extreme heavy weight. They should be trained that way for best results. DL's, cleans, etc come to mind.
The up-right row may be one of the better BB'ing exercises that can call upon the core (point of transfer of function/power) unit of the traps, back and delts to work as a group together. Try it with DB's for a change of pace, keeping the elbows out and inline with the body during the pull. Either BB or DB, when used right, the up-right row can be a great shoulder, trap and back mass builder. Good Luck