While you do need everyone to try on dresses to see the fit I would suggest taking your maid of honor and maybe one other available bridesmaid for the first round of shopping. This should give you a chance to see the styles and colors available, and night fight with seven people over what they each like best.
After your maid of honor and one additional bridesmaid try on a few styles you can get an idea of what style dress you want and maybe even the color and fabric too.
Once you’ve narrowed it down to three possibilities bring the rest of the group with you to the bridesmaid dress shop, or send them some options to see on WeddingtonWay.com -- an e-bridesmaid dress store.
Trust me, fewer people mean fewer opinion, and that equals less stress for you.