  Given a measured space X with commuting actions of two groups G and H
satisfying certain conditions, we construct a Hilbert C*(H)-module E(X)
equipped with a left action of C*(G), which generalises Rieffel's construction
of inducing modules. Considering G to be a semisimple Lie group and H to be the
Levi component L of a parabolic subgroup P=LN, the Hilbert module associated to
X=G/N encodes the P-series representations of G coming from parabolic subgroups
associated to P. We provide several descriptions of this Hilbert module,
corresponding to the classical pictures of P-series. We then characterise the
bounded operators on E(G/N) that commute to the left action of C*(G) as central
multipliers of C*(L) and interpret this result as a globalised generic
irreducibility theorem. Finally, we establish the convergence of intertwining
integrals on a dense subset of E(G/N).
