There are many ways that I have used over the years to set ground rules with children. It always boils down to this though;
How this is works is negotiated as we need to know it, sometimes in the middle of a game we might need to stop and work out the rules and make sure they work for everyone. This process of making group agreements rather than ground rules is an important part of developing social skills and having empathy for other people's needs.
With this comes an element of responsibility for your own self. Knowing where the boundaries are and making sure you stay with the group is important. As is the ability to notice your needs and do something about them.
This can't come at the cost of the place we are in. We should remember that we are visitors, in the home of the things that live in the woods and wilds.
I've been making some resources to help focus on these three responsibilities and I'm interested to hear how you start these sorts of conversations with the children you work with.