Problem solved :-)

I copied and modified linking between 3rd and 4th table (as described before), but miss VB code on Current event (for Licences subform, which on Current event refreshes subordinate subform Regkeys), which should be copied and modified analogically. This code makes requery operation which ensure relevant records in last subform.

Solution you propose will probably work (I tried complete nesting: one...

I have 4 hierarchical tables and want to display it all together as a form and 3 subforms, when subform displays (and allow to add/edit) only relevant items from each superior subform.

Tables are:
Clients --> linked thru id_client --> Orders --> linked thru id_order --> Licences --> linked thru id_licence --> Regkeys

Access' Form Wizard allows only form + 2 subforms. I tried to create last subform...