About appointment of internal auditor

Dear All,

 The below are the Real facts need support and advice.

Mr.X a CA  in Service,  working with XYZ hydro power company limited as internal auditor, one of the Subsidiary of ABC Group in which his payroll is processed currently , officially he was appointed through resolution in board meeting of the Company as a internal auditor in the XYZ hydro power company limited due to resignation of earlier Internal auditor  who is coming as consultant (Age 65 so resigned) .

Whereas, other Subsidiaries of the ABC group , say 6 to 10 public companies which should appoint Internal Auditor by virtue of Sec.138 and rule 13 approached Mr.X to accept as Internal Auditor of the said companies(6 to 10 Group Companies), so that they will pass a resolution in coming board meetings, Mr.X not in a position to accept that, because Mr.X thinking that, code of conduct of ICAI will not permit him to do so, Mr.X  requests us  to Assist  about this , Mr.X  said to the management, CS department that, Since he is employee of XYZ Hydro Power ltd, he can accept as Internal auditor of that company only, not for Group companies, they say, it is irrelevant where Mr.X  employed, can Mr.X be appointed as internal auditor of the Group Subsidiaries?. Can Mr.X  who is in service (not in Practice) Accept as Internal Auditor of the Other Subsidiaries of Group Companies?  required your Guidance on the said matter. 

Thanks in Advance 

CA.N.Devaraju