You are really not going to like the cost estimate you will get for doing this work. One way to approach it may be to look up a structural engineer and inquire about designing a solution to your problem and assisting you in contracting for the job. The engineer will be able to identify appropriate solutions and can supervise the work of the contractor to be sure the work is properly executed. You are going to invest a lot of money in this project, and the cost of the engineer may actually pay back by gettting you competitive bids. You are going to need to get permits anyway, so its really better that you hire the engineer, rather than pay your contactor to subcontract the engineering. Either way you will incur this cost.