HDB physical files separate from DIT

[matthew sporleder <msporleder@gmail.com>]

I'm trying to figure out if I can abstract a database's logical layout
(DIT) from being bound to specific files per 'database' definition,
and I'm not seeing any good tips in the berkeley db tuning docs.

For example:

I have ou=region1,dc=example,dc=com and ou=region2,dc=exmaple,dc=com. 
Right now the only options I see of separating these are to define
them in different 'database' sections.  I would, however, like to have
them both defined in one database, but allow the actual database files
(dn2id, etc) to be split in terms of size, or other definables. 
(usage stats, whatever)

Am I missing something obvious in DB_CONFIG like "max_file_size"?

Thanks,
_Matt