How do I play sound on a MacBook Air for a Skype caller to hear it?

Question

Skype

Hello!

There was such a problem: when I communicate with the interlocutor in Skype, he needs to play some sound files and YouTube videos so that not only the interlocutor, but also me can listen. I managed to implement something similar using Audio-MIDI - I made a device with 2 outputs.

And everything would be fine, if not for the fact that when, for example, some kind of sound comes on, the interlocutor starts talking and he hears himself + the sound that I reproduce on the computer. And it doesn't work out very well at all. It also happens that the interlocutor starts a wild background from all this, that I hear it all, he hears it - I have to turn off the microphone and the sound.

Question: how to play sounds from a poppy, but at the same time, so that the interlocutor does not hear himself when he wants to say something at the moment when some audio is playing, and so that there is no echo?

Thanks in advance to anyone who answers my question.