Field relationships don't support referencing multiple bundles

[TravisCarden]

You can't currently pick more than one value for the "Ref. bundle" field (target bundle for reference fields) on the "Fields" tab because Google Sheets validation doesn't support multiple dropdown selections. In the meantime, additional values can be hand typed, separated with commas. It will capture the necessary details for implementers, but the cell will get flagged as having an error, and it will break the entity relationship diagram (ERD). Obviously, though, a cleaner solution is desired longterm.

[greggmarshall]

Would the technique in this solve the multiple select problem (haven't had time to evaluate it)
https://gist.github.com/arthurattwell/aa5afc178624bdd6f46c2d0d28d06136

[TravisCarden]

That looks like an interesting possibility, @greggmarshall. It preserves the out-of-the-box interface for the simple use case but supports the complex use case with reasonable added complexity in the UI. I like it. This will be worth looking into, time allowing.