Is there any attribute like 'ou' which is populated for the entries in those containers, which can tell which container it belongs too?
If there is one, then you can filter using that attribute.
LDAP Filter does'nt support multiple OU Search in a single search, you must define a base DN.
To search in multiple containers select a top level container and find a common attribute, even a few letters common will work.
If you are unable to find a common attribute you can create one - find an empty attribute and run the update command to update the entries in the container with a common values.
UPDATE OU=test,DC=LDAPSoft,dc=com SET businessCategory='test'
subtreescope
Please make sure to run the update in Development environment before running the statement in production.