New toilet drain tie in location

[Spider]

I'm adding a toilet to what is currently a laundry room and I'm trying to figure out where to tie in the drain line. Can I add a long turn wye into a current toilet drain (red dot in pictures), or do I need to replace where the sink wye's in with a double wye (blue dot in pictures) to prevent the toilets from siphoning each other? For reference, the tie dye dot is the new toilet penetration. Thanks in advance.

 

[Terry]

You can wye in the second toilet.
The picture below is pretty basic, there should be wyes where it's drain with tees. The less change of direction the better.
A wye and a 45 is always better.

 

[Sponsor]

 

[Spider]

Thanks. The only difference between that iso and my setup, is the sink wet vent is downstream of the single toilet. That being the case, is it still ok to connect in the middle of the existing toilet drain, or do I need to tie in close to the sink drain/wet vent? I've attached an iso of my pipes with the potential new connection in red or purple. The utility sink will end up being a bathroom sink along with the other 2 sinks. Thanks again!