Accumulate the amount of condition types in accounting document

To accumulate the amount of condition types in accounting document without affecting the pricing display in billing document.

As an illustration :-

ZPXX   3500  
ZDXX  1000-  
ZWXX   500- 

(all condition types are shown separately in pricing view) 

Journal:  
Dr   Vendor 2000  
Cr   Sales    2000  (ZPXX - ZDXX - ZWXX) 

One way to do it is :-

Mark the condition types you want to group as statistical and remove the account assignment key. 

Create a subtotal in your pricing procedure that will add them together and put in the account assignment key for it. This way the individual components will still display on your pricing screen but FI will only get one posting.