Oh! Ok, I understand.
I do it for personal use for 3 feeds from 3 separate radios in my house.
I use Zello free (for Windows) on a dedicated PC, VOX function activated on the 3 Zello sessions, and the audio is fed from the 3 scanners from their earphone plug to audio inputs on the PC (a tower model with plenty of audio cards in/outs).
Zello free for Windows is rather difficult to find on Zello website as they promotes the commercial “Zello Works” version, you may have better luck downloading it from alternate websites. Google “Zello free for Windows” 😉