R help - Jan 2008 - clusteranalysis dendrogram

Dear all,

i have a little trouble with cutting an understanding the handling of  
dendrogram and hclust.
plotting clusters does work and it delivers a dendrogram. the problem  
is that the dendrogram shows lots of pretty small clusters and only  
some larger ones.
i know that this has to do with my data. But is there possibility to  
tell the plot function just to plot the clusters with more than x  
observations ?

thanks in advance

matthias