Photoshop :: Overlaying Text On Image

I've read how to fill text with an image by laying the image over the text and setting it as a clipping mask.  But I want to achieve a particular effect, and my text also has a surrounding shape.
 
Here is a snapshot of my layers:
 
You can see I have a group comprising the text, and a shape layer (with stroke) to define a border.  Both text and border are a mid-grey.
 
And I have set the group to "Color Burn" (over the image) to get an effect I like in the text. I would now like to achieve two separate things:
 
(a) retain just the text and border (with color burned image within), the rest as white (or transparent) 
(b) retain the text and border AND the paler image within the border, everything outside the border as white (or transparent)
 
In both cases, it would be far preferable to keep the text as a single editable text layer, and the shape layer as an editable shape layer, so that I can tweak both later.
 
I'm not sure how to achieve either!  The techniques I've see have the image on TOP of the text, but for my effect the image is UNDER the text.