InstallAware

I have an installer in which I want to make a logical grouping of utilities as components (as if they were in folders). To do this I was thinking about making the utilities sub-components of empty components (i.e. the component "testing" would not install anything but its subcomponents would). I've noticed that to enable "Entire feature will be installed..." on the categories I have to define the category as a component. However, doing that enables "Will be installed..." on the category, without selecting a sub component. I would like to allow the user to select individual sub components or choose the select all option on categories, but not be able to select a category without selecting at least one sub component.

I realize that my request may be difficult to understand so here are some truth tables:

Actual (only sub components defined):

Can select/unselect individual sub components.
Can Not select/unselect individual parent component.
Can Not select all from parent component.
Can Not unselect all from parent component.

Actual (sub and parent components defined):

Can select/unselect individual sub components.
Can select/unselect individual parent component.
Can select all from parent component.
Can unselect all from parent component.

Desired:

Can select/unselect individual components.
Can Not select/unselect individual parent component.
Can select all from parent component.
Can unselect all from parent component.