How to select a single record based on a multivalued candidate key and synchronize subforms to work with that record?

Question

Hi,

In a parent-form, I filtered a table on a candidate key consisting of multiple values, so the result should give a single record. Now I can't get the subforms to synchronize to that. It keeps showing the same record (with the possibility to loop trough all values using the buttons)
Either the applied filter does not work, or there is a problem in synchronizing the subforms.

I have set the Link Master Fields and Link Child Fields to the appropriete values.
Filtering is done using VBA-code: DoCmd.applyFilter

Any thoughts on how to synchronize or alternative ways to select the desired record?
Preferrably without using too much VBA.

Thanks