Railway group tickets

My relatives (6 people) are coming to Rotterdam on 29th August and are going back on 31st August. So, I bought 2 group tickets: 1 for the trip Eindhoven-Rotterdam Centraal and another 1 for the return trip. But the railway company sent me only 1 ticket. Is this ticket a return one or had I to buy a second ticket apart?
Is there anyone who has already bought group tickets and knows how they work?

Thank you!
Licia

What does the ticket say?

Enkele reis, retour or weekendretour?

Hi!

The ticket says:

Geldig op 29-08-2014
NS Groupsretour.

I think it is a return ticket but it's valid only on that day. I think I had to buy the other ticket in a second time.

Hi! Many thanks for your reply.

The ticket says:

Geldig op 29/08/2014
(Railway company) Groepsretour

So, I guess it is a return ticket but it is valid only for that date and I had to buy the other ticket separately.

Thanks again,
Licia

Problem solved. The return ticket confirmation was in the spam folder. Thank you!