I am coordinating a trip for a large group (30 people) in May. We will be arriving by plane in Amsterdam. From there we will be travelling to Oberhausen, Cologne, Brussels and then back to Amsterdam to fly home. We arrive on a Friday afternoon and depart Sunday afternoon for a total of 9 nights. We will be travelling by train but I am completely overwhelmed/confused by all of the available choices online so I have a couple of questions that hopefully those of you familiar with European trains can help me with.
1. Is it cheaper to buy online ahead of time or should I wait until we arrive in Amsterdam?
2. Should I look into a pass or purchase the individual legs of the journey separately?
3. Should I try to get group rates...half the group are students.
Thanks in advance!