Send links to open within a specific iFrame

Dearest staff,
I need to achieve this

I added the custom attribute on links as suggested, but it doesn’t behave as expected.

what should I do? (I need links from the dropdown Venues menu to open in the UXRviewer Iframe)

site is at gouxr.webflow.com

Thank you!


Here is my site Read-Only: gouxr.webflow.com