Two questions

[bkh]

If I am working with a layer stack where the only image layer is the background image how can I distort a group that does not include the only layer?

You’ll have to include the image in the group – you’ll need a (virtual) copy of it, or, alternatively, you can switch to document mode. In document mode, you can group the background image as well.

If I am working with a layer stack where there is an image layer other than the background layer and if I place all of those layers in a group, then will any distortion affect both the layer and the masks?

Yes.

Cheers,

Burkhard