Heya -- so on one form, you'd have multiple orders and each order will have multiple items?
What does your data table structure look like?
This shouldn't be an issue, really -- you connect IP to the Order table, then add the OrderItems table (and create the relationship).... The Order group will be repeating, and the OrderItems table will be repeating w/in it -- I also replied to your other question where you mentioned having nested repeating groups wasn't working and asked if you had any rows in your OrderItems table? The error message you were getting makes me think IP didn't detect that the items table was repeating....