We have 6 lines (seperate ext) on 7960G phones with roll over effect, but only one line, 1 have a voicemail box. We would like to foward noanswer on 2,3 4, 5, 6 to voice mail 1. Is this possible? We setup 2,3,4,5,6 noanswer to go to 1, but we could n...