I think you're looking for something like this.
This isn't usually something done by a cable alone, what you're looking for is a Audio Mixer, think a mini version of a recording booth panel that takes multiple sources and merges the signals.
Something like this but in stock: https://www.amazon.com/dp/B0824Q3WY8/ref=cm_sw_r_cp_apa_glc_fabc_ZBJDK946WH7DE5EXWEK8
Depends on what input / outputs you need. I've never needed one so can't be more help than just pointing you in the right direction.
Voice going to the PC might be a seperate issue. A seperate cheaper standalone mic could work.
This eventually won't be a problem though. Sony just announced a major investment into Discord, and Discord will be intergrated into the PS Operating System next year. Until then a mixers probably your best bet.