simultaneous pairings
 

My wife, a high school French teacher, has 5 classes of 20 to 30 students
each. She often has the students work in pairs and wants to create the
maximum number of lists of unique simultaneous pairings of students for each
class.

The number of possible pairings is n!/((n-2)!2!), and VBA behind Excel
produces all the possible pairs just fine.

The kicker is the creation of the unique lists. The problem arises because
of the need for the pairs to work simultaneously, and there can obviously be
no duplication of one student in any given list.

I've searched in vain for a pattern of pair selection that leads to the
automation of the process of producing the lists.

Any ideas?

Thanks.

Rich