iExpenses - is it possible to configure multiple Natural accounts for a single mileage schedule?

Hi,

My client has an expense template which includes a single cumulative threshold based mileage schedule. The normal convention is to attach a natural account which will apply to all the mileage expenses and then this is mixed with the user HR default expense account to derive the full account code combination.

My client would like to use different natural accounts to identify different types of mileage claims - such as Essential User / Home to Work mileage etc. Each of these are defined in the mileage schedule so is there a way (eg via a look-up table) to enable a different natural account to be used for each of the mileage types. If so where is this documented please?