As @mads0100 says you could write an ASCOM focuser driver. There's quite a lot of support for the ASCOM side of this and an experienced software developer shouldn't have a problem. Once you have an ASCOM focuser driver SGP can use that to connect to the camera lens and focus it.
The elephant in the room is that to do this you would need to connect to the camera API and implement commands using that which will read the current lens focus position and move the lens to a different position. From what I've seen of the struggles that people have doing things such as taking images and from what little looking at the camera APIs I've done implementing focus control on the camera side could be difficult to impossible.
Chris R