Except as hereinafter provided, it shall be unlawful for any person to accept appointment as guardian of any ward if such proposed guardian shall at that time be acting as guardian for five wards. In any case, upon presentation of a petition alleging that a guardian is acting in a fiduciary capacity for more than five wards and requesting his discharge for that reason, the court, upon proof substantiating the petition, shall require a final accounting forthwith from such guardian and shall discharge such guardian in such case, upon his delivering to a successor, properly qualified, the property with which he was chargeable: Provided, That the limitations of this section shall not apply where the guardian is a bank or trust company acting for the wards’ estates only: Provided further, That an individual may be guardian of more than five wards if they are all members of the same family.