How to add systemd service file to akmods package

I'm attempting to update my ZFS kmod packages and I released that for the akmods package I also need a systemd service file so that it runs early enough, but also so that the SPL kmod is built before the ZFS kmod. kmodtool doesn't give me any way to modify what files are packaged for the akmods package. I guess the simplest solution would be to create an additional package with just the service file and make sure the kmod-spl and kmod-zfs packages require it? Richard