Jimmy thanks for your reply.
I'll give you more information on what I am trying to do. I have created a subset of a parent schema i.e.
http://www.landxml.org/schema/LandXML-1.2/LandXML-1.2.xsd. My new custom schema is based on this one. What I would like to do is programmatically make sure that all XML files based on my schema pass validation against my schema and the parent schema. And I think if I could somehow validate my manually created schema against the parent one, I will not have to validate XML files against both schemas?
Does this make sense or am I going about this wrong?