I don't see why not - if you get the bit approx centered with respect to the piece that is to have the slot, and then ran the bit through the wood twice (once from each side) this would give you a perfectly centered slot.
It's then just a case of machining the tongue to fit (which would probably be more tricky, but through trial and error you could get it right.
My recommendation would be to mount the bit in a router table.
regards,
Martin