Azure Traffic Manager and Sub-Domains

Question

Hi

I have a question about configuring Azure traffic manager in a priority configuration with Azure App Gateway V2.

1) A number of web apps with custom domains:
foo.my-website.net
baz.my-website.net
bar.my-website.net

2) A V2 App gateway with a public IP address
The app gateway is setup with routing rules/host headers, so that a request from a browser for
'https://baz.my-website.net/' is routed to the backend pool webserver using its internal '.azurewebsites.net' domain name.

There is no "www" domain for these applications, so only subdomains will be used.

This is all working fine. Now, I wish to mirror this environment in another region to provide regional failover capability.
I am trying to configure Azure traffic manager to perform priority routing, but I am unable to find any documentation about how to
perform the configuration when using subdomains.

I want requests for (for example)
https://foo.my-website.net to go via traffic manager to the primary application gateway and from there to the back-end webapps.
I have 2 specific questions:

1. In my DNS configuration, I have an 'A' record pointing to the IP address of my application gateway,
   How do I configure the '.trafficmanager.net' CNAME so that I can support the sub-doman routing ?
2. How do I configure the Endpoints in traffic manager to support the endpoints? I note that I am unable to create a separate rule for each subdomain.