Yes, it has been what you called a closed circle in the past.

They are both closed circles, and all the players know one another.

The new parents bent over their baby, a closed circle.

A knot used to create a closed circle in a line.

The guy who is determined to break the closed circles of Britain.

Dancers form a closed circle, putting their hands on each other's shoulders.

The council has come a long way from the closed circle of designers who started giving themselves awards in 1981.

It seems a closed circle, into which we are unable to break.

The same applies to distribution and use within a "closed circle of users".

Such closed circles seem to exist everywhere in this orchestra.