Generic XMLPort

Does anyone know wether it is possible to create a generic XMLPort (for import)?

What i try to accomplish is the following: I will create several XMLPorts -each importing a different XML schema. However they all share the same header. What i want is a single XMLPort to read only the header-part (and skip the rest of the XML).

This will allow me to check if it make sense to import the complete XML. Trouble is, Navision wants me to enumerate all possible tags in the XMLPort…