Well with the situation set up the way you have it now that is your ONLY option ... all of the sales must go on your return ... how you get the others to "chip in" to pay the extra taxes on your return is up to you.
NOW ... if you really want this to split 3 ways you will need to form a formal partnership, get a partnership EIN from the IRS , file a partnership return and open a broker account in the partnership's name.
