Combined Surface Mechanics in Civil 3D
Kyle Groves, a Technical Specialist at ATG, delivers an instructional walkthrough of of combined surface mechanics in Civil 3D.
From the ATG YouTube Channel.
Thanks, Kyle. Nice of you to cover the mission critical nature of the Surface model's Edit stack order.
It might be a better idea to create and maintain your combined surface models in a separate project drawing(s). Then employ them as DREFs in your design and publish drawings.
Managing the surface model's data interactions and potential updates is easier to create, maintain, and update that way.