Is it possible to exclude the root domain and only configure event publishing for a subdomain with Meta Conversions API Gateway?

When you configure CAPI Gateway, it uses pixel data to track FB events from the server side.
Inside the Meta’s Conversions API Gateway Hub, website configuration allows you to manage domains that send events to CAPIG. Using this setting, you can limit domains that send data to the CAPIG and allow only required subdomains. 

So using this tool you can configure the CAPI Gateway Hub to send server-side events for blog.example.com but not for example.com.