How to do project wise accounting for items issued?

We have multiple projects using the same items under one inventory organization.

We want each project to get the item cost based on their individual purchase order since they can agree todifferent rates with the same supplier for the same item?

Currently, at the time of item issuance, the average cost is accounted against the project but we want the actual cost of the item to be accounted against the project.

How can this be achieved?