We show that, within the framework of SUð5Þ grand unified theories (GUTs), multiple vectorlike families at the GUT scale which transform under a gauged Uð1Þ 0 (under which the three chiral families are neutral) can result in a single vectorlike family at low energies which can induce nonuniversal and flavorful Z 0 couplings, which can account for the B physics anomalies in R K ðÃÞ. In such theories, we show that the same muon couplings which explain R K ðÃÞ also correct the Yukawa relation Y e ¼ Y T d in the muon sector without the need for higher Higgs representations. To illustrate the mechanism, we construct a concrete model based on SUð5Þ × A 4 × Z 3 × Z 7 with two vectorlike families at the GUT scale, and two righthanded neutrinos, leading to a successful fit to quark and lepton (including neutrino) masses, mixing angles, and CP phases, where the constraints from lepton-flavor violation require Y e to be diagonal.