xcode - Allow my iOS App to Appear in 'Open In...' list on Phone Number Click

I'm building a calling app, and the aim is to allow users to select to call a phone number in another app, and for our app to open in the 'Open With...' list, so users can call the person on our app instead of the default calling app on iOS.

I've found that I can add document types to identify valid formats which can open the app. What I'd like is when someone clicks a phone number in another app or online, they get the option to open it with my app. To link a phone number, obj-C uses a URL string, and the doc type for that is public.url.

How do I differentiate between that and a normal URL so my app can open when someone clicks a phone number in another app? Thanks in advance.