  In this paper, we study intertwining operators between subregular Whittaker
modules of $\gl_N$ generalizing, on the one hand, the classical exchange
construction of dynamical quantum groups, on the other hand, earlier results
for principal W-algebras. We explicitly construct them using the generators of
W-algebras introduced by Brundan-Kleshchev. We interpret the fusion on
intertwining operators in terms of categorical actions and compute the
semi-classical limit of the corresponding monoidal isomorphisms which turn out
to depend on dynamical-like parameters.
