This can be run in conjunction with another ice-breaker or party game to help make things more interesting.
Before the meeting arrange with one or more individuals to be the mystery person or persons. Give each of these a number (a low value one eg between 1-10) depending on how many will be at the meeting. These individuals have to keep it secret from the group they were picked and the number they were given.
In the session run a game that gets everybody mingling (such as Ape, Man, Girl). The mystery person/s have to remember who was the person they met that was their number. For example, if they were given the number five, it was the fifth person they met.
Announce to the group who the mystery persons were and the person they met on the number you gave them. Give both a small prize if you wish.