co-host video sharing

On our stage we have two monitors (for the audience to see) and at our A/V station we have two monitors- one to monitor Zoom, the other for our meeting materials.

The A/V monitors are screens 1 & 2, while the audience monitors are screen 3.

At times we will have a visiting speaker who logs into Zoom and is given co-hosting privileges. He would often share his screen, which will appear on the Zoom monitor (1 or 2, depending on the preference of the A/V team member serving as the host), but not on the audience monitors.

How do we get the audience monitors to show what the visiting speaker is sharing?