Advanced pdf - add instructions but consolidate from multiple lines

Hi there,

I am creating a custom purchase order advanced pdf template. The clients requires having a line at the bottom of the pdf that displays manufacturing instructions. This comes from the charge items Purchase description. This is easy to pull as I can use item.purchasedescription. I however need to consolidate this information from multiple lines, to avoid repeating the same instruction.

Here is an example:

There are three line items on the Purchase order for the Printing charge item. In this table that is displayed below the purchase order items, I just want one line to be displayed, as these are all the same.