How do you turn off tax calculations for intercompany transactions in R12?

I need a bit of assistance on how to turn off tax calculations for AGIS Intercompany Invoices in EBTax.  This was set up by an outside group and I was very little documentation by that team.  It appears that this is working (not calculating) for some of the countries but not all.  I have been through all the rules and setups and can't see where this can be done (comparing a country that does work against one that doesn't)

Could anyone provide where to look or where it should be?

Thank you in advance

Annette Leggett