So in lieu of all things pandemic, this new ‘rule of 6’ has come into play in England today. Groups of 6 or less. There are exceptions of course, which are underpinned by newly-released legal requirements. This new law explains what you can and cannot do.
And it is of course terribly straightforward! Let me explain - basically, what needs to happen is there needs to be a gathering, and you need to be part of a qualifying group to be able to join in that gathering. However, you must make sure that you do not become a member of any other qualifying group at the gathering, and you must not mingle (now a legal term, no mingling for you, citizens of England, okay?) with others at the gathering who are in other qualifying groups but who are also participating at the gathering.
These terms and conditions will depend a little bit on your type of gathering, so your qualifying group may be taking part in a significant event gathering, or a relevant outdoor activity (which is another name for a gathering), or a sports gathering (to name but three). Ultimately, as long as you don’t mingle and ensure your qualifying group is arranged appropriately at your gathering, then everything will be legally acceptable.
And in case you think I’m exaggerating for comic effect, I’m quoting directly from the legal infrastructure we are expected to understand and adhere to. Links in the comments. Also, note that the details of this new law were published 15 minutes before they came into force (i.e. 11:45pm last night). Another way in which this government has treated you in such contempt during this pandemic.