We consider vector-valued solutions to a linear transmission problem, and we provethat Lipschitz-regularity on one phase is transmitted to the next phase. Moreexactly, given a solutionu:B1 subset of Rn -> Rmto the elliptic systemdiv((A+ (B-A)chi D) backward difference u) = 0inB1,whereAandBare Dini continuous, uniformly elliptic matrices, we prove that if backward difference u is an element of L infinity(D)thenuis Lipschitz inB1/2. A similar result is also derived for theparabolic counterpart of this problem.