I think you could do something with velocity scripting here to deliver one email with 1 or 2 or 3 pieces of content, based on what the lead selects. Sanford Whiteman - my javascript is embarrassingly rusty, but does that sound feasible?
Sure, it's a matter of String.split(";") and then printing each value (not JS but VTL).
(Old thread, though -- all this stuff was falsely bumped up after the Community upgrade, unfortunately.)