Seems that they said it is; however, you could do all this with Zoom, for instance. To be in the room muted and with no volume, disconnect the audio connection

Seems that they said it is; however, you could do all this with Zoom, for instance. To be in the room muted and with no volume, disconnect the audio connection. To ask for someone's attention, send them a direct chat message (not to Everyone). And of course you could always leave the Zoom meeting and rejoin later.