Plumbing in wall toilet

[Mark Burbank]

I'm plumbing a bathroom with sink, in wall toilet and bath/shower. The in wall toilet drains down the center of the framing base plate and the tank completely fills a double wide stud bay, so I'll have to run the vent pipe in the adjacent stud bay between the toilet and bath/shower. My question is whether I can use a combination tee to combine the sink drain with the toilet drain?

 

[Terry]

The combo is a good fitting for that. And then the lav gets vented.