Contraction Problem

I am using Rhino 6. I have a 3D model, I have a building of 30 mb and I will put 6 of these buildings side by side. How can I reduce the size of my model?

Hello- insert the building as a block.

http://docs.mcneel.com/rhino/mac/help/en-us/index.htm#commands/block.htm%3FTocPath%3DCommands%7CAlphabetical%7CB%7C_____7

-Pascal