[R] R Hierarchical clustering leaf node

[Qunfeng]

Hello,

I am new to the R package. After I use R to perform the hierarchical 
clustering,  I am only interested in retrieving the leaf nodes that share 
the last common ancestors. As illustrated below, I'd like to retrieve (B, 
C) as a cluster and then (D, E) as another cluster.    Any chance to do 
this in R?  Thanks! BTW, I just subscribed to this list (not sure if the 
subscription is succeeded), please copy your anser to my personal email 
(qfdong at iastate.edu) -- Qunfeng

                                 |
		          |
                         -------------------------------------------
                         |                  |                       |
                         A             ---------             -------------
                                        |        |             |            |
                                        B      C            D           E