Series of Events: All Group Members Meeting Each Other Exactly Once

We have a networking group of 100 people, where every day 10 people should meet. Eventually everyone should meet the other 99 people exactly once, rotating the group with every meeting.

During a standard, group-based MixerSeater event, there is a given number of round tables. The groups of more or less 10 people are seated at tables, meeting each other in the same room, concurrently, over the course of 3-5 sessions.

Here we need to modify this scenario, as there is no one big event. We have plenty of small events and they can be face-to-face or virtual.

Determining the Number of Events Required

Up to a point you proceed exactly as you would with a standard single, group-based MixerSeater event.

But depending on the number of people in your group, you need to take a few tries to find the best combination of “tables”, “seats at a table” and “sessions”. In this particular exercise the number of seats at a table describes how many participants will be joining your single event. Every table will be a separate event, and sessions mark a new batch of events. Every person in the group will attend only one meeting in a given batch.

Here is an example. Let’s say we have 9 people in our group (just to make the scale small enough to demonstrate). It’s a magical number that allows us to create a perfect seating chart without any duplicate meetings, where everyone meets everybody else. To achieve this goal we need to generate a seating chart for 3 tables with 3 people each and 4 sessions.

The resulting seating chart gives us 4 batches (sessions) of 3 events (tables). 12 events in total, 4 per person. Every one of them will be attended by 3 people and each person will participate in only one event in each batch.

Still, the produced seating chart can be a little confusing when you send it to your attendees, as this is not exactly a seating chart, but a general plan for you. It would be best if every event had its own designation, right?

Creating the Event Calendar

For now, the next step has to be done manually. You have to export your seating chart to an Excel file. You will get a list of names. Next to each you will find a set of numbers. Every number marks a particular event number in one batch of meetings. And what you need is the sequential number of each event to be able to say: you are participating in events number 1, 4, 7 and 10 and your dates are below:

To get general meeting numbers to give to each person try this:

1. Remove the top row of our table (just for the purpose of clarity).
2. Put 0 (zero) instead of "Session 1" in cell B1.
3. Enter the formula “=B1+3” in cell C1. Mind that 3 is the number of meetings in every batch. Be sure to use your number of meetings there.
   
4. Copy this formula to each cell in the top row
   
5. Put "Event Batch 1" through "Event Batch 4" in cells G1-J1 (use your number of sessions here, too).
   
6. Enter the formula “=B$1+B2” in G2
   
7. Copy the formula for each event batch / participant.
   

And that’s it! Now you have a table that informs every attendee in which event he or she will be participating. In our example Participant 1 will be attending event number 2 in the first batch, 4 (second batch), 8 and event 12 in the final batch.

Working with Event Calendar

When you know the exact dates (say event no. 1 is on 1st August, event no. 2 on 2nd August, etc.) simply replace:

• "1" with "1^st August",
• "2" with "2^nd August", etc.

It may be necessary to use copy / paste special / values only to be able to replace easily. But there are some more sophisticated Excel tricks to achieve this even faster (see " VLOOKUP" to start off with).

And your event calendar can finally look like this:

If you want to see who will be attending on a specific date just use a simple Excel filter:

Enjoy your events and don't forget to mention that MixerSeater did the job for you!