  The interlayer pair-tunneling (ILT) mechanism for high-$T_c$
superconductivity is able to predict the dependence of the (optimal) critical
temperature Tc on the number of layers n within an homologous series of layered
cuprate oxides. We generalize the mean-field procedure employed to evaluate Tc
within an extended in-plane Hubbard model in presence of ILT, developed for a
bilayer complex (n = 2), to the case of n = 3, 4 inequivalent superconducting
layers. As a function of doping, we show how a nonuniform hole-content
distribution among different layers affects Tc. In particular, depending on
doping, the onset of superconductivity may be ruled by inner or outer layers.
The latter result may be related to recent experimental data of Tc as a
function of pressure in Tl- and Bi-based layered superconductors.
