F5 APM and DUO Security protecting external website access with 2FA

We want to protect external website's login page with 2FA using DUO Security. We already have similar setup for OWA which works OK but this is all internally. Our F5 APM is doing AD authentication and then opens DUO iFrame page with 2nd step options i.e. DUO Push. Once authenticated with DUO Push it opens OWA page, job done.

I have now built another virtual server, using same AD authentication as in above example and I need to open external website with DUO iFrame to continue with authentication and login. How do I take it to external website, do I need new webtop pointing there?