How to design a template with a fixed number of rows in a column but allowing text wrapping within t

We are designing an RTF Template for a pre-printed cheque format.

There is a section for listing the related invoices in two columns:

invoice 1 amt           invoice 6 amt
invoice 2 amt           invoice 7 amt
invoice 3 amt           invoice 8 amt
invoice 4 amt           invoice 9 amt
invoice 5 amt           invoice 10 amt

As there are 2 boxes (one for each column) for the invoice list, the number of rows to be printed is also fixed e.g. 5 rows in one box. More, the invoice number may need to wrap to the next row like:
invoice 1 amt           invoice 5 amt
invoice 2 amt           invoice 6 amt
invoice 3 amt           invoice 7 amt
invoice 3                  invoice 8 amt
invoice 4 amt           invoice 9 amt