There was a year or two where TM did away with the combination plumbing and had separate hose attachment points for the toilet and gray tank. So yes, it can be done. Apparently some gubment agency was trying to make it so campers had to dump black in one hole and gray and another. The campgrounds all pretty much said no thanks.
Don’t want a poopy hose transfer? Get a couple short hoses and a Y-adapter. Then you can put the Rhino Blaster on the Y-adapter before the main hose to flush both small hoses and tanks without transferring anything.
2x
https://a.co/d/jc6MYEL +
https://a.co/d/5nzZ2xR
Or you can rebuild as standard and get yourself a plumbing guard from the factory for ~$150 + shipping.