Two external definitions for one message

Hi experts,

I've got one problem:

I'm developing a new sender interface, other firm gave me 2 xsd schemas to use as external definition.

The second schema is in fact a sub-node of the first schema.

What is the correct way to manage this two schemas in XI?

I've tried to cut and paste second schema into first, but no luck because second schema has different names of the xml tags.

Now I've imported the 2 schemas as external definitions, but I think I must link them, but I don't know how.

Could you please help me?

thanks

Fabio