Make your query as you wish, make sure you select the partner number, then on the form, add a group on a field. You'll have to specify if you want the field to be ordered in ascending or descending order. Then, you can add group header and group footer, on the header, you will put the name of the partner and his number so it will not be repeated in the detail part. Use the assistant to test a sample form, the assistant will ask you about grouping value, chose a field and look the result.
Sorry, I can't help you more since I don't know you datas structures