Custom Menu Items based on a button or link click

I have a possible client who doesn’t want to mess with having visitors be required to create an account or log in but they want to change the navigational menus based on a user type. So for example, if the site is for a medical device, they want physicians and patients to have access to the same site (same URL), but they want to hide certain links in the nav from the patients. I suggested that we handle this by creating sub-domains and if they click on patient-centric info, they go to the patient site and if they click on physician links, they go to the physician domain. They wanted everything to be on the same site.

I know, it’s a wonky request. Because it could be done simply with multiple domains or even done with pages and well categorized menus. But I’m trying to see what there is for this specific request.

Is there some plugin or functionality, that when I click on a link or button, it adds an argument or something that changes the navigation? Perhaps it changes a class or style that I can the display to none for the menus? So if it’s on, menu 1 is visible and if it’s off, menu 2 is visible?

Thoughts???

Thanks, Chris