Looks like that is not possible out of the box. The best thing you can do is sort externally column data. See org.richfaces.renderkit.AbstractExtendedTableRenderer.rowGroupChanged(FacesContext, ExtendedTableHolder) for more information on how grouping works: http://fisheye.jboss.org/browse/RichFaces/trunk/ui/extendedDataTable/src/main/java/org/richfaces/renderkit/AbstractExtendedTableRenderer.java?r=12428
Thanks for the reply, at least now I'm sure that it is not possible.
Do you think it is worth to send a request to the designers of
ExtendedDataTable for this requirement?
Thanks for your help.
feel free to create such RFC in our jira with detailed description and the guys will check it for sure.