Currency fields not changing all in same record

I have a module (Accounts) that I need to set different kind of currency amounts

Each amount can be on one local currency, or USD

Normal Sugar behaviour is that when you change the type of currency in one field, all currency fields change to that currency.

What I need is for each field to work independent and stay in the currency is originally defined, and not to be converted to the base currency, so that I can have different currencies shown at the same time