In the past you couldn't use Europe maps in a USA vehicle because the radios were different (different RF frequency channels). Some have swapped radios. Servicemen stationed in Europe sometime will do this. There is an outfit somewhere that does convertions. Dunno if the 2014 is different, however.
You may find that using a portable GPS with Europe maps, or your phone is more cost effective.
2011 Grand Cherokee Overland V8, 2009 Liberty Rocky Mt V6, 2000 Grand Cherokee Laredo I6, 1979 CJ7 I6 Quadratrac