Install utility sink(s) drains to 2" drain that washing machine drains into

[frilbo]

The picture below shows the current 2" drain w/p-trap for the washing machine - with a 1-1/2" vent extending up from that (sorry for the poor cropping. I'll take a better picture when I get home tonight). That is the washing machine to the right. I would like to add 2 utility sinks to this drain/vent if that's allowed. 1 utility sink would be in this room to the left of the washing machine. The other utility sink would be in the garage behind this concrete wall but 40" higher (split level house).

So questions are:
1)Is it even permitted to have these additional fixtures tie in to this same drain (not the washers, but the one the washer's goes into)
2)How do I tie into this and in what order? (the current washer drain's sanitary tee is only about a half inch above that clean out - maybe less)

I was thinking to cut that off and start with a double fixture sanitary tee, but that only address one sink and the washer. What about the other sink in the garage? And how do I splice above that cleanout with so little material?

Any tips would be much appreciated.

 

[breplum]

The tee can be cut out and the clean out fitting drilled out with a special RamBit, which allows re-gluing of the tee.
You could put a new 2" tee on top of the c.o. tee and run that to the distant higher split point and then tap higher up to vent.
UPC would allow u to use a double fixture figure 5 fitting on top of that 2" tee but code requires the P-trap for laundry to be not less than 6" nor greater than 16" off the floor so stacked tees are better.
UPC requires wet venting like this to be on the "same floor" but does allow up to four fixtures max. on wet vent. It would work.
Functionally but not legally you could just do a 2" fig.5 and stack the high 2 x 1-1/2 tee and it ought to work but is not legal, technically, as far as I can imagine.

 

[Jeff Handy]

My brain is melting trying to picture all this.

Meanwhile, this might be obvious, or already stated, but maybe you can eliminate a standpipe and just dump the wash water into your new utility sink.
Maybe add an AAV to the top of the old standpipe if needed for extra good venting?

Less chance of backing up and flooding due to high discharge rates of newer washing machines.

 

[frilbo]

The tee can be cut out and the clean out fitting drilled out with a special RamBit, which allows re-gluing of the tee.
You could put a new 2" tee on top of the c.o. tee and run that to the distant higher split point and then tap higher up to vent.
UPC would allow u to use a double fixture figure 5 fitting on top of that 2" tee but code requires the P-trap for laundry to be not less than 6" nor greater than 16" off the floor so stacked tees are better.
UPC requires wet venting like this to be on the "same floor" but does allow up to four fixtures max. on wet vent. It would work.
Functionally but not legally you could just do a 2" fig.5 and stack the high 2 x 1-1/2 tee and it ought to work but is not legal, technically, as far as I can imagine.

Just want to make I understand correctly. Like this?