I'm not sure I understand your problem.
Do you mean you have multiple files that use the same icon type such as folders, .pdf, .txt, etc… in SliderDock and you'd like to differentiate each icon?
If so, each icons should have a different name.
Moving the mouse within an icon will show it's name.
Otherwise you can change the shortcut icon in the "icon settings" menu.
As for a list, SliderDock doesn't have any.
I might add a list to allow users to reorganize the rings order in a future version but for now you will need to use the method previously stated.