Hi. I'm adding a laundry sink next to my washer and was thinking I could just cut off the top of the standpipe where my washer now drains, then plumb in a tee to come out of the wall in order to put in my sink drain and ptrap. I would then just have the washer drain into the sink. The only problem (is it a problem?) it that there is a ptrap in the wall a the bottom of the washer stand pipe and the sink would now have two ptraps. issue or nonissue?

Thanks