replication without making the consumer database readonly

I have an Openldap 2.4 environment with 2 servers, one serving as provider for 2 databases and one as consumer.

On one of the databases I only want to replicate certain entries, filtered by objectclass. I use sync repl for replication. Now I would like to be able to write database entries on the consumer server, which are not covered by the filter and so are not replicated. But Openldap sends me a referral to the master on write attempts if I use the updateref directive. If I don't use this directive, I get error 53: unwilling to perform. Is there a way to have part of a databases entries to be replicated and others being allowed to write locally?

Alternatively I'm considering to split the suffix into several databases.

Kind regards, Michael