Split and simplify the following sentence while retaining its full meaning: Whereas Directive 92/30/EEC does not apply to groups which include one or more investment firms but no credit institutions; whereas it was , however , felt desirable to provide a common framework for the introduction of the supervision of investment firms on a consolidated basis.
 Simplified version:
Directive 92/30 / EEC does not apply to groups comprising an investment firm ( s ) but not a credit institution . However , it was considered desirable that a common framework should be established for the introduction of supervision of investment firms on a consolidated basis .