Get individual cell selection on JFace TreeViewer and cell based contextual menu

Question

I am an eclipse RCP developer. Still kind of a rookie. I have a requirement which says that I have to have a viewer which shows the comparison between 2 objects in the viewer with different categories (columns) and the user should be able to take action based on the variance. That means I should be able to select individual cells as well as multiple cells of the same category and invoke a contextual menu on them. I am emphasizing on the fact that I have to have a tree like structure because I will have parent as well as child items to multiple levels. Please suggest how can it be achieved.