Shakespeare makes a VHF/FM splitter....you plug the antenna in on one side and there are 2 leads on the other side. One goes to the VHF and one to the stereo.
That said, my experience with the splitter has been disappointing. I picked up noise in my VHF, had no AM reception, and I think it impacted my VHF reception. I wound up taking it out.
If you have room, the best antenna for your stereo will be either a 4 or 8 ft fiberglass one that matches your VHF antenna. Alternatively, I've had decent luck with both the dipole (wire) $5 antenna as well as a rubber duck auto antenna. Both of these can be stashed underneath the console.