I've never heard of building time in a multi turbine aircraft as big as a Merlin unless it's a pay-to-fly occupat..... Oh I see, Nevermind.
I really don't see how your proposition makes any financial sense. "splitting the cost" on an aircraft with an operating total cost of at least $1000/hr doesn't seem like a logical way to build time. Unless your typing people in the aircraft this sounds pretty fishy, I'm sorry if I'm misreading you.