How can I crawl based on metadata instead of folders in Documentum

I have Sharepoint 2010 Foundation and Search Server Express with the standard Documentum Connector. We are crawling for objects in Documnentum, but the problem is the folder structure is huge so it takes forever.

Currently, we are just using this at a high level and it goes through all sub folders and then afterwards we filter out all folders from the searchable results.

http://dctm<clientapphostname>/<repository name>/<cabinet name>/<folder name>

Is there any way to ignore folders from the start or query based on some sort of metadata, i.e. a simple DQL query to find what wee need would be something like:

SELECT * FROM my_custom_type WHERE custom_attr1 = 'xyz'

And not have to crawl through half a million folders to find 100k objects