We are creating a new "extension package" for our AppExchange 1GP that integrates it with a third-party managed package and want to use 2GP for this "extension package". The third-party is willing to share an installable beta release of their 1GP with us along with its installation password (that way they know we can't use it on production orgs, just for our integration package development).
Do you know if it is possible to create our 2GP with a dependency on that beta release, or do we need them to also share the equivalent full release's version ID with us? I'm hoping one or other can be used, with us installing the beta 1GP on our scratch org to satisfy the dependency. Would this work?
I've searched for detail around this but can find nothing - the Salesforce documentation focuses on the simple use cases as always... :(