Redirection Host as Proxy Host root.

[LocalBoomer]

Is your feature request related to a problem? Please describe.

I like to use a (likely) cursed setup where I have a subdomain redirect to a home/landing page but have subpaths of that subdomain proxy to relevant services. e.g:
homepage.mydomain.tld ==> proxy pass to http://homepage:82
arr.mydomain.tld ==> 301 to homepage.mydomain.tld
arr.mydomain.tld/sonarr ==> proxy pass to http://sonarr:8989/sonarr

Currently, I can't do this with NPM.

Describe the solution you'd like

I would like an option to choose one of my redirect hosts as the 'main' host for a Proxy Host. This would allow me normal access to the Custom Locations and Redirects features without having to use any custom nginx configuration. Would also save me having to set up weird 'null' arrangements like having the root subdomain point to http://null:404 making things more confusing when trying to see what does what at a glance.

Describe alternatives you've considered

Currently, this result (my cursed pathing setup) can be achieved in NPM by using a combination of null routes and custom nginx configuration in a normal proxy host. But, this removes the primary (at least for me) benefits of NPM - those being ease of setup (no need for custom nginx config/formatting) and clarity of information.