20 Pa.C.S. § 7773: Impartiality - UTC 803.

If a trust has two or more beneficiaries, the trustee shall act impartially in investing, managing and distributing the trust property, giving due regard to the beneficiaries' respective interests in light of the purposes of the trust. The duty to act impartially does not mean that the trustee must treat the beneficiaries equally. Rather, the trustee must treat the beneficiaries equitably in light of the purposes of the trust.