Adding custom scheme redirects

Problem/Motivation

Adding the ability to add custom schemes such as imessage:// and facetime:// to a redirect for email clients etc that don't support custom schemes.

I am specifically looking at the two schemes above for a customer that is completely apple based and would love to have the ability to link directly to iMessage / FaceTime. If you enter the url into a browser or into html text, a prompt will come up to open the corresponding app on either MacOS and iOS

Proposed resolution

As far as I can understand, the field that processes the link is a standard url link? Perhaps there is some sort of injection that could allow the expansion of supported schemes?