Currency usage in Release Strategies

We use, within our organisation, both requisition and Purchase Order release straegies. The release objects associated with these can only be assigned to a single class per object and as a result of that, a "common" currency has to be used when having a characteristic that is associated with value. In a multinational environment, this can lead to discrepancies in the levels for release due to changes in exchange rate. Whilst this is something that can be maintained each time exchange rates are changed (monthly in our case) it is already time consuming & will become more so as we implement in other countries where we have to deal with a curreny other than our base (Euro). Is anyone aware of a method which will enable the strategies to be defined against company code currency.

Thanks in advance