Adding sink in in utility room

[basementbrewer]

I want to add a utility sink in our downstairs utility room. There is a bathroom adjacent to this room with shared wet wall. I wanted to ask the pros the proper way to tap into the existing sink supply and drain lines. It appears that to tie into the copper supply lines I need to add tees to branch off for the new supply. For the drain line, what is the correct way to connect the new sink drain to the line. Can I take off the current PVC elbow and replace it with a tee with the two sinks coming into either side of the tee, or do I have to extend the drain line out and route a new line to the vent above where the current drain line connects to the vent for proper venting. Maybe these diagrams will help, maybe not. Thanks in advance!
I
I
I
I Sink One
I---------I
I Sink Two
I

or

I
I
I
I---new vent connect--I
I I
I Sink One I
I---------I------------I---I
I Sink Two
I
I

[hj]

There may be more than one way to do it, or it may not be done at all. From your description, I assume the drain line is horizontal to the sink. If it is a 2" i.d. pipe, then you can either use a 2" x 1 1/2" X 1 1/2" "double elbow", or you can add another tee. If it is 1 1/2" i.d., you cannot connect two sinks to it.

[basementbrewer]

The line does run horizontal to the sink and is 1 1/2" (i.d.?) so it sounds like connecting another sink is not an option. Is it an option to run a new 1 1/2" line from the main vent/drain line for the new sink?