ACM Metadata load automation

We just downloaded the latest version of ACM released in March. I am using the ACM BRs to load hierarchies from a table into OS dimension. I have populated the member and tree tables as needed and everything seems to be working fine, however we are not seeing an option in which this load would follow a “merge” like behavior.  Currently if my table does not have a specific member or relationship. Onestream is just deleting/orphaning those members.  Is there a way to have this behave like merge that it does not delete existing members in Onestream which is not present in the table or incoming load. We had similar behaviour in prior version of ACM but are not seeing this now.