Message Filter Extension and multiple servers

In the documentation for a Message Filter Extension it states:

If you have servers that can help your app extension determine how to handle a message, you must add the Associated Domains capability to your Xcode project and specify those domains.

(https://developer.apple.com/documentation/sms_and_call_reporting/sms_and_mms_message_filtering/creating_a_message_filter_app_extension)

The words servers and domains are in the plural.

If it's possible to specify multiple servers/domains for a Message Filter Extension then how is that done? There's no documentation nor reference for that. If multiple domains can be added to the info.plist then what is the iOS behavior in that case? Can the extension supply/change which domain is used at run time?