Require multiple GL accounts for tax postings

We have 2 different tax regimes, used by a single operating unit. For our GL tax postings from AR and AP, we would like to use a separate GL account for the 2 regimes, and the same for the AR and AP transactions, ie 4 GL accounts in total. Can we achieve this without customising the SLA? We have been unable to do this using standard functionality, as even though we can give the 2 tax rates different GL codes to be used by Payables, we cannot then separate out the AR postings into the 2 regimes.

Any thoughts appreciated!