preformed ponds

First of all I became a ponder quite by accident, or should I say by the fury of Mother Nature. In 1996 a huge tornado swept through our town and surrounding area. My brother and his wife lived in a small town north of me. After the tornado was over, there was a preformed pond lying in my brother's back yard, intact, and had no damage except for the roofing nails impailed in it. Since no one claimed it, I brought it home, removed the nails, filled the holes with aquarium epoxy, and it took me 3 weeks of trial and error, digging and filling, leveling and backfilling, but by golly, I did it, I put that pond in my back yard, and planted a raised flower and rock garden around it.  I put goldfish, a few plants and a bottom filter in it and have enjoyed it all this time.  Well guess what? I want more. I plan on retiring in 5 years, and I am planning my backyard oasis for my enjoyment after I retire.  I bought a 170 gallon preformed pond about a month ago. I thought I was going to bring it home and connect the two together, somehow, someway. Ha!  Every person I have talked to about joining the two ponds, gives me the "gee, I don't think that will work" line. I am determined to connect these two together. I know I will have to take in consideration the changing of the seasons, the ground expanding and contracting, and so on. But there has to be a way. I had even considered placing the new pond partially above ground and connecting the two with a stream, pulling the water from pond to pond by means of a waterfall in the upper pond, which would keep the stream running. Anyway that is my brainstorm.  The one that is already in the ground is 120 gallons.  Any suggestions?