On a page https://www.paypal.com/sk/cgi-bin/webscr?cmd=_batch-payment-format-outside I see that in 4. and 5. column I can order optionally information. I want to ask what will see the recipient in describe of payment. Will he see the text which I will write in 4. or 5. column ?
I did a post on Mass Pay : http://www.amitnyamtabad.com/paypal-masspay-feature-to-save-transaction-fees/ with all the screenshots, I am sure that is going to help you out.