coterie

A circle of individuals who associate with one another for a common purpose.

The new junior employee joined our merry after-hours coterie.

A tightly knit coterie of executive powerbrokers made all the real decisions in the company.

A communal burrow of prairie dogs.

The coterie was located in the middle of our wheat field.

The population of each coterie constantly changes over a period of a few months or years, by death, birth, and emigration. But the coterie boundary remains about the same, being learned by each prairie dog born into it.