Well, call dish, they will gladly activate it for you, but after 6 receivers, you will need to pay for a totally seperate account per 6 boxes (so say 3 accounts, 18 boxes, w/ basic top 60, if you can get it @ the promo, 45*3 = 135 + your taxes, not to mention anything over 4 receivers will not be free!)
(Why your doing it, its your business, not mine, im not gonna jump to conclusions via the ~18+ receivers, one post, however I, and many others can privately draw some really strong ideas)