Did you mean 3/4" slots, not 1/4"?
I'd use a router, rather than a jig saw. however a jig saw just inside the lines will remove most of the material leaving the final clean up for the router. A hand held circ saw will do the same, but I'd use a right angle guide and NOT saw right up to the half way point. Leave some for the jig saw to nibble away and clean up with a chisel.
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)
Last edited by woodnthings; 03-27-2016 at 11:12 AM.