I suspect that I'm going to end up recommending that you index those files with the DataFinder and query the files/groups you want to include in the graph and configure the Group property you want as a property column in the Search Results area of the NAVIGATOR. But I won't know for sure until I understand the scope of what you want to accomplish. How many of these Group property histogram graphs do you want to create on the same report? What other elements or other pages do you need to put on this same report?
If you have DIAdem 2012 or later, take a look at the shipping example "Evaluation Wizard for the Search Results of the DataFinder", which is the first example in the "Mining and Loading Data" section of the shipping examples.
DIAdem Product Support Engineer
I know this post is quite old, but is your previous comment still the primary advice even for newer versions of Diadem (i.e. 2018)? So search and filter for the specific property of interest using DataFinder and set as a property column?
I'm in the same boat as the original poster (and a lot of people)...the 65K channel restriction for loading data into Diadem was way too limiting, so I setup my parsers to load single values into properties instead of channels, but now it seems that I can't really do much with them. This seems like a pretty significant flaw in Diadem that I would think it should be better able to deal with by now. Hopefully there is better support for charting property values now and the answer will be different.
Let's say that I have 3 Datasets all with a property "TotalFuel" and different values in each group, So what I will like to do is to plot this values in a 2DAxis object.