Exporting texture Alpha from a group

While looking for a good Maya PitsNPeaks alternative, I have been tinkering with further scripts to improve artist texture workflow.

One of the things I am working on is a neat little script that allows an artist to work on an image's alpha in a group named 'alpha' in the source PSD document, which is automatically copied over to the output file's alpha channel when it is exported, provided it is a texture that requires it (eg, an 'a' or 't' texture).

The intention is that an artist will be able to edit and update the alpha channel as fluidly as any other texture map a material requires.