Question: Is it possible to share an Authorizer or HTTP Api

I've seen multiple threads and discussion around splitting up services into their own serverless.yml file setups.

Including this example showing sharing an API Gateway.
https://github.com/serverless/examples/tree/master/aws-node-shared-gateway

Is it possible to share an HTTP Api, instead of the RestApi in this example? I have a question on SO regarding splitting up a HTTP Api service using an authorizer which falls into the same question.
https://stackoverflow.com/questions/60968313/sharing-an-authorizer-between-different-http-api-services-in-aws-with-serverless

I have seen various threads on Export/Fn:Import information, but I cannot see documentation on what should be exported and imported in the different services to get this working.

For example, if you Export an Authorizer/Cognito User Pool, what should value should you export and where/how do you Fn: Import that value in sub-services?

Start with the aws-node-shared-gateway example and compare its RestApi setup with HTTP Api services in serverless.yml. Review the linked Stack Overflow discussion and the issue's Fn::ImportValue question; done would be documented, working guidance for sharing an HTTP Api authorizer or a clear statement that it is unsupported.