Add additional text to end of PURL in Create Link box

Ability to select a Ontraport Landing Page as the link, but then add more to the end of the URL.

The only way I can currently see to do this is use a custom URL that links back to an Ontraport landing page.

I'm currently using it to pass information to a landing page for the 'Display Settings / Only show this block if the page URL contains specific text' function, which is laborious & lacks flexibility should I want to change the domain the Membership Site is on (currently building a site that will be moved to a live domain at a later date)