Kind of thinking out loud...

[![enter image description here][1]][1]


Duplicate the group with effects..

[![enter image description here][2]][2]

With the **duplicate** group highlighted, choose `Layer > layer Style > Create Layers`

[![enter image description here][3]][3]

You'll then have a layer for ever style applied.

Hold **<kbd>Command/Ctrl</kbd>** and click the thumbnail in the Layers Panel for the Outer Glow to load a selection based upon its transparency.

[![enter image description here][5]][5]

Delete all the style layers and the duplicate, create a new layer and add a mask based upon the selection of the Outer Glow layer.

[![enter image description here][6]][6]

Result is a layer matching the size and drop off of the outer glow but you are free to add whatever you want to the actual layer.

-------------

Now.. if you need the glow to *dynamically* change, well that may be a conundrum in itself. `:)`


  [1]: https://i.sstatic.net/2vGsa.png
  [2]: https://i.sstatic.net/Hi9gE.png
  [3]: https://i.sstatic.net/Dkmtz.png
  [4]: https://i.sstatic.net/2wQS4.png
  [5]: https://i.sstatic.net/lrGLX.png
  [6]: https://i.sstatic.net/AZQzF.png