Option to split up source files in modules

I would like to see an option to split up the source files (spells.txt, feats.txt, classes.txt, skills.txt) in modules, so if you'd like to not use a sourcebook like Ultimate Combat (yes, I use d20pro for Pathfinder), you could easily just disable the option for that sourcebook and all spell lists, feats and classes from there vanish from your game.
This also has the advantage that sources are more easily identified as already implemented and it could improve the community generated content creation, because the workload could be easier split up. Especially for small source books like the Faiths of Purity/Balance/Corruption.

My suggestion for the implementation would be additional textfiles named similarly like spells.uc.txt, feats.apg.txt etc and a textfile which adds the description for those abbreviation and lets the program know, which files to read.

Something like this:

Code:

#sourcelist.txt
crb|Core Rulebook|spells,feats,classes,skills|mandatory
apg|Advanced Players Guide|spells,feats,classes
um|Ultimate Magic|spells,feats,classes
uc|Ultimate Combat|spells,feats,classes
lang|Languages Addon for Skills|skills
conc|Concentration checks for Skills|skills
fop|Faiths of Purity|spells,feats
#etc

This suggestion on Google Moderator: http://goo.gl/mod/v1Iw