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'
Please make sure to run the update in Development environment before running the statement in production.