Can working days be used instead of calendar days in a standard infolet?

Summary:

Calculate aging period using only working days instead of calendar days.

Content:

The aging requisition lines infolet in Purchase Orders area of Procurement module displays the no. of requisitions lines that are pending according to a period range. Our requirement is to use only working days instead of calendar days in the infolet to calculate the aging period of a requisition line as client doesn't want to consider holidays, weekends in the aging period. Aging Requisition Lines is a standard infolet provided out of the box and we would like to know whether it can be modified to suit our requirements and what would be the steps to take to achieve