Is it possible to display one QR code that can be used to pay multiple addresses in one transaction?
Absolutely it is.
Create a QR code from a dictionary of addresses and amounts that you wish to send funds to like so:
{address1:amount,address2:amount,...addressn:amount}
and feed it to an application that uses it to construct a transaction.
I have written an example of how to construct a transaction
here.
Hope this helps