Shrek- Cathedral Window

[Crisp image]

I am tasked with making the cathedral window in Shrek where the dragon comes through and smashes it. We want to make one window that appears to break but it retracts back into the set and leaves some small shards in the opening. The shards are the easy bit but what about the rest of the window. My thought is that the window is made up of 4 quarters that are held in place with a Ka bookie and when triggered weights and pulleys move the 4 bits out of the opening leaving the remaining shards behind.
Any thoughts?
Regards
Geoff