[asterisk-users] Rate sheet "normalization"

[Markus]

Hi,

this question is not Asterisk specific, but since there are so many 
experts present on this list, maybe its OK to ask anyways.

I'm having a hard time "normalizing" rate sheets from different 
providers. What I mean with this: the goal is to always get the cheapest 
rate for a given destination. What I would like to do is throw like 10 
rate sheets from different providers together and as output get a single 
rate sheet with only the cheapest rates. However, some providers are 
listing a country, lets say Germany, as code "49" with a specific rate, 
and another provider will list each city individually, and each code 
separately, e.g. Berlin "4930", Hamburg "4940" etc., and probably 
different cities have different rates as well. Now, if the "49" route of 
the first provider is cheaper, my system (a2billing) will still use the 
more expensive "4930" code because it is more specific.

I'm looking for some awesome, smart tool that will automatically 
"normalize" all these code differences and output a clean ratesheet with 
only the cheapest rates.

Does such a thing exist? I wonder how everyone else is "normalizing" 
their different rate sheets. With a homebrewn script?

Thanks!