Section 203B:3 - Designation of substitute or successor custodial trustee(a) A person having the right to designate the recipient of property payable or transferable upon a future event may create a custodial trust upon the occurrence of the future event by designating in writing the recipient, followed in substance by: "as custodial trustee for ____________ (name of beneficiary) under the Massachusetts Uniform Custodial Trust Act."(b) Persons may be designated as substitute or successor custodial trustees to whom the property shall be paid or transferred in the order named if the first designated custodial trustee is unable or unwilling to serve.(c) A designation under this section may be made in a will, a trust, a deed, a multiple-party account, an insurance policy, an instrument exercising a power of appointment, or a writing designating a beneficiary of contractual rights. Otherwise, to be effective, the designation shall be registered with or delivered to the fiduciary, payor, issuer, or obligor of the future right.Mass. Gen. Laws ch. 203B, § 3