"smart" transposition of key signatures

[Kieren MacMillan]

Hello all,

I've got a piece in which the key centres move thusly:

   E major  -->  F minor  -->  A major  -->  F major  -->  E major

I need to transpose it up a few pitches, as it was originally written for 
medium voice, but is going to be sung by a high[er] tenor.

  \transpose e g ==>    G major  -->  G# minor  (= B major) -->  C major  -->  
Ab major  -->  G major

would be great… except what's actually happening is

  \transpose e g ==>    G major  -->  Ab minor  (= Cb major, with 7 flats!!!) 
-->  C major  -->  Ab major  -->  G major.

Is there any way (like the "naturalizeMusic" function for individual notes) to 
ensure that the key signatures in a transposed piece are the "most logical"?

Thanks,
Kieren.