Grouping of bugs in webstart demo

Hello

It ´s the first time I use glazed Lists and I´m very impressed, but I need some help.
So far I had a look at some screencasts and tried to use the new information to do it on my own.
But I saw in the webstart demo, that the bugs are grouped in the table ( like(www(5)) and this is my problem. I don´t know how to do this.
At first i thought it is described in the GroupingList & FunctionList Screencast, but this screencast didn´t help me. I know I can group the datasets with GroupingList, but I don´t understand how to transfer this into a jTable that it looks like in the webstart demo.
This way I need some help.....

Regards Benjamin