How I can query attribute value from policy (Text Driver) to validate parent and child relationship

I need to validate that an object (parent) exist in the eDir before create a new  child object.

Example:

I create the parent, manually from Identity Console / Object Management.

Parent Object:

CN: 00001

Name: unit 1

ParentID: 0000

The next  objects will be create using a Text Driver

But, if in the text file the user copy a ParentID that not exits in the eDir,I need validate it and abort the operation.

Child Object

CN: 000010

Name: unit 10

ParentID: 0001

Process OK

Child Object

CN: 000010

Name: unit 10

ParentID: 9999

Process abort

I tried using a "find matchin" in a match policy but dont work.

Where CustIDPresidenciaJefa is a parten and must exists to create the CustIDUnidadLaboral

I tried using "destination atribute" but dont work.

Exists anyway to do its?

Best,

Cesar.