Feature Request - Cross account lambda authorizers

We currently have one account that handles all API/GQL authorization for our apps and our apps all live in their own accounts. We started creating new app sync projects in new accounts and would like to be able to use the same lambda auth from an external account for lambdaAuthorizerConfig.
In the current docs:
"Multiple AWS AppSync APIs can share a single authentication Lambda function. Cross account authorizer use is not permitted."
https://docs.aws.amazon.com/appsync/latest/devguide/security-authz.html

Start with the linked AWS AppSync security authorization documentation and the lambdaAuthorizerConfig configuration described in the issue. Determine the account and IAM constraints for using an authorizer Lambda externally, then define how cross-account authorization should be supported and verified for AppSync APIs.

Written by the indexing model from the issue text.