Hi Herchi --
sorry for the delayed reply.
You can change the order of groups, but it's a little weird because of the fact that groups are stored in a database.
You can drag and drop to put one group as a child of another, etc.
But to change ordering, you have to EDIT the group (right-click choose edit) and then adjust the "Display Order Weight". The lower the value, the earlier it will display with its siblings.