Brep made out of joined surfaces/seamless joined surface being used as brep

Hello, 

I have a definition that uses a brep component at it's start. In order to apply the definition to an object in rhino, the object has to be a single seamless surface. But I'm looking to use a few joined surfaces as the brep component in the definition, without success so far. 

Another option is to somehow create a surface which can be folded and manipulated (without control points) but cannot be exploded into a couple of different surfaces like a regular surface could once it is being folded. 

any ideas?

P.S 

I'm attaching a 3dm file that contains a folded seamless surface which works weel as the brep component inside the definition. I found it here so I'm not sure if it was constructed by mesh tool or by another way. If someone would know how to create another surface just like that it will be great. 

thanks in advance!