Render it with another camera
OrthographicCamera mStageCamera;
OrthographicCamera mFixedCamera;
SpriteBatch mBatch;
@Override
public void render() {
mBatch.setProjectionMatrix(mFixedCamera.combined);
mBatch.begin();
//render "static" elements
mBatch.end();
mBatch.setProjectionMatrix(mStageCamera.combined);
mBatch.begin();
//render "movable" elements
mBatch.end();
}