Hi Oli...
It's only necessary to place a post once. The categories are just vague, collections. Most everyone just looks at the current posts or uses the search feature as there are so many posts to sort through.
As to your problem, it will take a macro or code. All connection information is "contained" not in the actual shape but in the connectors attached to the shape. It could be either a connector or some other 1-D line variant. In addition, since you really want to explore the number of branches (or roots), connected to a shape, and the number of sub-levels is undefined and can vary, the algorithm needs to be "recursive", I think.
One basic attack would be to select a shape, then loop thru the page connections collection, identify which connectors are attached to that shape, and store both the connector ID, the connector end, and the total number of connections made. Then, for each attached connector, go thru and find what shapes are attached to the opposite end, store those. Select each opposite end shape and repeat the process, except now, the total count ought to be reduced by one for each sub-level shape, as it's "lead-in" connection has been previous counted. The process re-iterates until shapes with only one connection are found, presumably, these are the terminal shapes
Hope this helps. It will take some programming skills.
Wapperdude