Enter comma or tab delimited names. You
  have some control over where students are placed:
- Bloggs, Joe:2 (for example)
  will force Joe to group 2.
- Smith, Sally:a  and  Starr, Ringo:a  will
  force Sally and Ringo into the same (randomly numbered)
  group
- Hawking, Stephen:b  and  Einstein, Albert:c will make sure Stephen and
  Albert are in different groups (and also different from Sally and Ringo)
- Astair:Fred/4 means do not put Fred
  in group 4.
- You can combine letter preferences with number
  prohibitions like this: Cooper, Gary:a/2. That would put Gary in
  group a (with Sally and Ringo) while making sure that group a was
  not the second group. (You cannot use letter prohibitions; just use
  a different letter.) Note that using too many of these combinations might
  make a solution impossible.
If you specify a group number larger
  than the number of groups created, the person will go to the last
  group. If you specify a letter that falls too late in the alphabet
  it will be ignored.