Cyclocross - CX and SSCX races and training

Finally, I am going to have to change the shifters, as I just can't use them from the drops, which is basically where I am for the whole race, so the entire setup is going to get a rethink.

Can these Di2 sprint shifters be used without the sti units? They'd be out of harm's way, unaffected by mud* and perfect for use in the drops.

*possibly