Accounts Payable

We have issue posting our bills to the correct AP account. We have multiple AP account in our COA such as AP CAD, AP USD, and Tax remittance.
Our concern is that whenever we create a bill it will automatically post to the Tax remittance AP account which makes our P&L report incorrect. And there's no option where we can select or edit the account on the bill.
Current transaction journal of our bills is this:

Debit     Expense

Credit           Tax Remittance AP

which we need our posted transactions transaction journal to be like this:

Debit     Expense

Credit         Accounts Payable CAD

Can someone help us or teach us how to fix it.