Take a look at the online tutorials
here. Also do a search about sites here in this forum, it has been discussed often.
The site can be hotlinked into the building file and vice versa. With Solid Element Operations (SEO) you can trim the site with the building to achieve what you describe.
Erika
Architect, Consultant
MacBook Pro Retina, 15-inch Yosemite 2.8 GHz Intel Core i7 16 GB 1600 MHz DDR3
Mac OSX 10.11.1
AC5-18
Onuma System
"Implementing Successful Building Information Modeling"