It is not possible to do it inside GiD, and standard exchange formats like IGES doesn't support this 'polisurfaces'

In Preferences->Meshing->Unstructured, the 'Skip entities automatically' allow the mesher tocreate elements with nodes on different surfaces.

In the Mesh->Mesh criteria menu the user can also expliciltly select some lines to be jumped or not, then from the meshing point of view it's like a 'super-surface'