excel parent child data driven testing

Hi

Apologies if this is a newbie question but I am new at this.

I have built some data driven tests using excel as input & output and have managed to make some great forward strides and am really excited at the possibilities ahead.

I cannot grasp how to deal with a one to many relationship in the xml.

I have to test an api along the lines of the following;

PurchaserDetails

    Name

    Address

    Phone

    Email

    Item Ordered

        ItemId

        Name

        Quantity

        Cost

The details are captured on line and tehre can be any number of items ordered for one purchaser.

How can I do this with data driven from Excel? Can I do it with two data sources and build a relationship?

Thanks

Keith