The Central Civil Services (Classification, Control & Appeal) Rules, 1965
7. GENERAL CENTRAL SERVICE:
Central Civil posts of any Group not included in any other Central Civil Service shall be deemed to be included in the General Central Service of the corresponding Group and a Government servant appointed to any such post shall be deemed to be a member of that Service unless he is already a member of any other Central Civil Service of the same Group.
Government of India Orders/Decisions: