make a new object and attach all the objects you want to rotate to that object. Then you can just disable the mesh renderer from the central object and rotate it.

If I understand you right, you are looking for something like this:

var rotation : Quaternion;
var radius = Vector3(5,0,0);
var currentRotation = 0.0;
function Update()
{
currentRotation += Input.GetAxis("Horizontal")*Time.deltaTime*100;
rotation.eulerAngles = Vector3(0, currentRotation, 0);
transform.position = rotation * radius;
}

More Details
Sin and Cosine are your friends.

Basic circlular motion is given by the following formula:

x = cx + Math.sin(time)*rad;
y = cy + Math.cos(time)*rad;

cx,cy are the center of the circle and

rad is the radius of the circle .

As time goes from 0 to 2*PI (or multiples thereof), the x,y values will describe a complete circle.
Here is an example of for more contact (http://watchserials.net/) using this formula. Attach this script to the object you wish to move.

onClipEvent(load)
{
cx = Stage.width/2; // coords of center of circle (center of screen, in this case)
cy = Stage.height/2;
rad = 100; // radius of circle
speed = 6; // speed of travel (seconds to make a complete circuit)
speedScale = (0.001*2*Math.PI)/speed;
}
onClipEvent(enterFrame)
{
var angle = getTimer()*speedScale;
this._x = cx + Math.sin(angle)*rad;
this._y = cy + Math.cos(angle)*rad;
}

You could try and make a new object and attach all the objects you want to rotate to that object. Then you can just disable the mesh renderer from the central object and rotate it.