Yes. Select all the brushes in a folder, and drag them to empty space at the bottom of the panel. Then right click and delete the group.
Have a little play with the new management system before you delete groups. How about making a new group, and dragging all your favourite brushes into it?
That will remove the brush from the original, so you need to select a brush band chose new brush preset which will make a copy. Drag the copy to your new group and you are good to go. Restoring or loading the original brush group/set will place it in the panel with all its original presets.
Okay. So I tried that and it worked but when I go to select a new brush (I have many) it puts the brush I selected from the list in a folder again. I really don't want to do the make a new group as I remember them better when I select the brush. I just don't want them to always load in a folder because I don't want to have a list of them. I just want the brush set I select to be there each time.