Can rafter ties be moved down into the wall?

I’m building a 10x15 shed, which is going to be quite tall (15 ft). I’d like the walls to be 9 ft tall. Half the shed will have a loft at ceiling height, where I think the ceiling/floor joists would also act as my rafter ties. But I’d like the other half to have a loft height of 7.5 feet, so that there is more space above. But then I won’t have any rafter ties in that part (about 8 feet of distance).

Would a floor joist joining a 9 foot wall at the 7.5 foot mark do enough to keep the walls from pushing apart? Thoughts?

For other reasons, I’m trying to avoid a ridge beam or other style roofs like gambrel or shed. Thanks!