I wrote:
There are other ways one could specify which internal schema entry/tree to use when that is not specified in the LDAP update operation - e.g. cn=schema,cn=config & children could hold mappings from OID/schema element name to the entry which should receive the update.
I meant, a mapping using wildcards or regexps to match element OID/name.
Not sure if that's any better. I wonder what X.500 servers do.