Crystal Reports Adding Tax rate tables to Crystal form

Message

   Hello,

I am designing an AR Invoice form to work with Accpac. I am not sure how to add the tax percentage. 

In the AR Table I have the field CODETAX1, CODETAX2,CODETAX3 etc. In the Tax table there is a field called Authority. I am having trouble with the linking. 

CODETAX1 = GST 

CODETAX2 = PST

CODETAX3 = HST

AUTHORITY can be any of the above: GST or PST or HST etc.

The reason I am unable to just do a calculated field is the form is for Quebec where the base amount is not the same, since Quebec taxes are taxed on tax.

Anyway I can add this with a subreport or if someone can help me out with the linking ?

Thanks,
Debbie