Technically it can, but at the moment OSBee’s API (specifically, the manual station run API):
https://github.com/OpenSprinkler/OSBeeWiFi-Firmware/blob/master/docs/OSBeeAPI1.0.0.pdf
is different from OpenSprinkler’s API, so OpenSprinkler’s firmware as is can’t switch OSBee’s zones. But what you asked is a good point and I can definitely add the manual station run API (specifically, the /cm command) to OSBee firmware and that way it’s compatible with OpenSprinkler.