cs-cart shipping cost combine. 3.0.6 multi vendor

i have cs-cart multi vendor- normally i set vendor's shipment. but someone purchase product then shipping come out sperately. i want sum .. for example) A vendor -----usps ,,,,,B vendor ----USPS C vendor ----FEDEX some client purchase A,B,C vendor's product original version A VENDOR shipping -----USPS (3~~4DAYS) ====10 US$ B VENDOR shipping -----USPS (3~~4DAYS) ====10 US$ C VENDOR shipping ----FEDEX(1~5 DAYS) ====5 US$ --------------------------------------------------------------------------------------- SUB TOTAL 25 US$ I WANT UNDER A,B VENDOR shipping -----USPS (3~~4DAYS) ====13 US$ (SUM WIEGHT THEN CALCULATE SO MUST BE CHEAP) C VENDOR shipping ----FEDEX(1~5 DAYS) ====5 US$ --------------------------------------------------------------------------------------- SUB TOTAL 18 US$ ******************HERE IS PRODUCT SHORT DISCRIPTION 1-----------------------MAKE A ADDON --- WHICH CAN ACTIVE OR DISABLE. ACTIVE ----- COME OUT SUM ,,, DISABLE---COME OUT SEPERATLY. FOR UPDATE OF CS-CART. --- function when shipping name is same then SUM product wieght then calculate shipping cost. 2-------------------- vendor does not need shipping cost on vendor admin panel. so please bid only know well CS-CART SOLUTION. DO not bid beginner ----- DO NOT BID beginner. i need SPECAILIST OF CS-CART MULTI VENDOR. contact SKYPE :pilotloe PLEASE PLEASE ONLY SPECAILIST BID FOR THIS PROJECT