How to propagate headers to a remote graphql endpoint (subgraph)?

Hello, Apollo community!

I’m in the process of migrating an existing monolith graph to federation (subgraph/gateway). Part of the reason for migrating is due to the need to federate a 3rd party graphql endpoint for consuming content via a CMS provider. The endpoint requires its own set of authentication (i.e. bearer token, access token, etc.) and I’m unfamiliar if there is a way to propagate headers to subgraphs. Looking at the Apollo Router docs there does seem to be a way to propogate headers, but can this also be achieved using @apollo/gateway?

The 3rd party graphql endpoint generates a schema at request time to ensure it is always up-to-date with the current content.