Moving Terrain or entire house as a unit?

I built our house in Personal Architect last year as the real thing was being constructed to help me visualize choices. It worked great!
Now we are building an ADU on the adjacent lot and I would like to keep what I have and build in the same project because they will relate to each other and I need to see sightlines with the existing house. Right now the existing house model sits in the middle of a large site that extends into the adjacent property lines. I really want to recreate the terrain but have it centered between the houses instead of the existing house. Is there a way to either move the terrain or house as a unit? or even move that center point?