Pipelines Search Record

I'm using pipelines to link QB records to associated folders on Google Drive - each record has a field called [Google Drive ID] which holds the ID provided by Google Drive. I then embed that folder view in the record to display all the files on the record. So far it's working great.

Here's where I'm having trouble. If a user uploads a file to Google Drive, I want pipelines to update the associated record. Below is what I'm doing but I'm happy to take an entirely different approach if someone has a suggestion.

1. Every hour, search for new files within a specific Google Drive folder. Pipelines successfully finds matching files, providing the folder ID in a list called {{a.parents}}
2. For each new file, search for the record where the folder ID matches [Google Drive ID]. I can't figure out how to perform this search - I think I need an advanced query but everything I try fails.
   • Adding a condition on [Google Drive ID] doesn't provide an option to search within the {{a.parents}} list
   • '{{a.parents}}'.HAS.'_fid_512' successfully pulls in the folder ID, but '_fid_512' doesn't get evaluated (512 is fid for [Google Drive ID]
   • '{{a.parents}}'.HAS.'{{b.google_drive_id}}' results in a blank value on the right side of the expression

Any guidance or suggestions would be appreciated. Thanks