create e-tickets with order slip or invoice

[PrestaSam]

Hi you guys,

I sell tickets for my band. I create a ticket (virtual product) for each concert. If someone buys 5 tickets, one invoice is created as well as one order slip. We now ask the one person who orders them, to share the invoice with the other 4 people. It works but it's not perfect.

Now I'm looking for a way to create the amount of e-tickets someone buys so that every ticket has a unique reference. For instance: Orderno + 01 etc. I'd like to just use the standard Prestashop templates which I edit of course.

Is there any way to make this possible? 

Thanks very much for your help!