If you are logged in an IZ A and you are searching a specific item belonging to a specific record, you will find it only if this IZ A owns this item. If you are logged in IZ B that does not own any item of this title, the holdings are merged into one or several records (deduped) and you cannot distinguish which item belongs to which record.
Example:
IZ A has 6 records of one title; each record has one item.
In the IZ A, searching this title, you will find 6 records, each one with its item
IZ B has no item of this title (no holdings).
In the IZ B, searching this title, you will find 1 record with the 6 holdings merged.
What we would like to achieve is that the search returns the same display of results, with all holdings visible in all IZs, regardless of which IZ owns the item.