Our phylogenetics results support our hypothesis very well. However, the trees are very large (~300-500 entries) with each tree containing multiple subtrees having 30 to 50 'leaves' which represent numerous strains/variants of the same species. In order to reduce the complexity of viewing these phylograms, we would like to collapse those subtrees and relabel them as 'XXXXXXXXX sp., 30 leaves". Which of the available tree viewing/editing software packages would be best for this?