ROUND Slice inside slice, or round content inside content

[Rjdel]

Pardon the rather elementary question but I am struggling with slices and masks.
My goal is to have a small circular slice, on top of (or in front of) the larger full screen slice.

I have tried to layer the main slice (slice 1), then an inverted circular mask (to allow all to show except the small circle where I want slice 2), then slice 2 (much smaller), and a regular circle mask to crop slice 2 to just the circle (that matches the inverted mask on top of slice 1).

But no matter how I arrange, the masks affect all slices.
What am I missing?

If the polygon tool allowed for circles, I suppose that could work instead of slices/masks, eh?

I am sure it is simple, so again, pardon, and thanks for any help.
-Rob

[Rjdel]

Never-mind. I just discovered INPUT masking!