How can I get a uniform white balance on a batch of JPEG images?

I have shot many photos of the same subject in JPG. Since I have shot for many hours with different light conditions the white balance is quite different for all the shots.

I would like to automatically adjust the white balance to have an uniform white balance across all the shots (while I want the luminosity to be the one of the shot).

I have tried some tools:

• 
  

  Scripts based on ImageMagick here, but they are quite primitive: one just computes the transformation so that the selected pixel is (0,0,0), so without preserving luminosity, the others are too slow

  
  


• 
  

  darktable: with this I can create a set of transformations on a picture (say, the first) and then apply it to all the others. The problem is that for the white balance it computes the transformation for the first image and then applies exactly the same transformation to the others, without recomputing the transformation for every image.

  
  

Suggestions?