slabs that large will twist
You can cut them into 6" wide planks, but there is an issue with twisted boards on a table saw....kickback. The twist will cause the work to either wedge against the blade or the fence and jam or kickback.
A better method would be to use a circular saw and a straight edge to rip the pieces into 6" planks. The next issue is that the edges won't be 90 degrees to the faces for proper joining and glue up because the wood is slightly twisted. A 6" jointer will surface and square the edges ...if you have one?
Planing or a router sled will waste too much material. JMO. It's a tough call to just abandon the whole top without trying something. also JMO.
The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)