Hi there, if you are referring to shortcode from https://wordpress.org/support/plugin/video-conferencing-with-zoom-api/ then, restricting a join link is not possible via plugin because the join link shown from shortcode will show publicly in your site unless you have hidden that page from a membership plugin or something.
This is something a host will need to do via Zoom’s end either by locking the meeting or disallowing someone from the waiting room itself.
@tommy Is there anything else that needs to be added from Zoom’s end for controlling such behaviour ?