I have the following list. I need a way to concatenate the dates between the new entry(s). The number of dates can vary between new entries.

New Entry
9/2005
10/2005
11/2005
New Entry
9/2005
10/2005
11/2005
New Entry
9/2005
10/2005
11/2005
New Entry
6/2006
7/2006
New Entry
6/2006
7/2006
New Entry
9/2006
10/2006
New Entry
12/2006
1/2007
New Entry
3/2007
4/2007
New Entry
3/2007
4/2007
5/2007
New Entry
4/2007
5/2007
6/2007
New Entry
4/2007
5/2007
6/2007
7/2007
New Entry
5/2007
6/2007
7/2007
8/2007
New Entry
5/2007
6/2007
8/2007
9/2007
New Entry
5/2007
6/2007
8/2007
9/2007
New Entry
6/2007
8/2007
9/2007
New Entry
6/2007
8/2007
9/2007
12/2007
New Entry
6/2007
8/2007
9/2007
12/2007
01/2008