Record Management. Record Model relation

Hello,

Can anyone explain me what is the relation functionality in the record modeller?

I mean the part between rol visibility and attributes.

Help sap says:

"Optional: Enter a relation. The relation expresses the relationship between the element and the record above it. Input help is available for selecting the relation. (You maintain relations in registry maintenance in the dialog box for Area, tab page POID Directory.) "

You can define this relations using SRMREGEDIT in the Direct POID tab but I can't find any example where you can use this part of the record modeller.