I think it would be tacky to tell a school your other financial offers. In all honesty, if it's as great of a program as you claim, they may really want you but there would certainly be plenty of applicants they really want as well, so don't try to play the special snowflake card to them or it could potentially backfire if perceived as a character flaw. If what you say is true, they will give you the aid they allocated to the top candidates, and, if you deny it, they will simply shift the list up one spot.