When flying FPV drones in a group setting it is very important to choose appropriate video transmission frequencies so you don't interfere with others that are flying near you. What are the best channels to use ( depending on where in the world you are ) for groups of 2-6 people?
To answer this question, there are two things you need to know. First you need to be able to map the various channels and bands to their frequencies. Second, you need to understand Intermodulation Distortion (IMD). The quick explination of IMD is that two or more radio frequencies can combine to cause interference on a third frequency.
Using the above chart you can see how the different bands and channels overlap. In general, when flying with just one other person, you are fine to choose any two channels that don't overlap frequencies. However as you add more people to the mix, you have a higher chance of causing IMD. To help with that issue, many races now operate using a group of channels called IMD5 or IMD6.
If you are in a group of 5 people, the recommendation is to use R1, R2, F2, F4, and E5. If you are in a group of 6 people, use R1, R2, F2, F4, F8, and R8.