There are several ways to combine those.
Some are right, some aren't.
Here is a laundry tub and washer.
The tub to the left could have been a lav, which roughs a bit higher.
I have a washing machine with 2" drain, properly vented. Can I connect the drain of my bathroom sink which is vented, to that same 2" drain.
In my case I have the washer drain pipe running alone a wall meeting the lav drain pipe at 90 degrees alone the other wall. The 2" washer drain continues in a straight line. Which coupling do I use to connect the two? May be a wye & bend? Can a wye & bend be installed on its side. In the photo a sanitary T is used, I understand that a sanitary T can not be installed on its side.
CAN you do it" Maybe, it depends on HOW you make the connection and we don't know how that is. Your description is too confusing to try to follow HOW the pipes meet or are installed, or WHY you have to do it in the first place.
Licensed residential and commercial plumber
I was just trying to get an understanding as to which drain fitting to use when two drain pipes meet and join at right angles in the same plane. I wanted to consolidate some drains to avoid more holes through the floor. All the examples I am getting are when the waste pipes join to a vertical line, not two joining in a more horizontal connection.