  To solve the relativistic bound-state problem one needs to systematically and
simultaneously decouple the high-energy from the low-energy modes and the
many-body from the few-particle states using a consistent renormalization
scheme. In a recent paper we have shown that one such approach can be a
combination of the coupled cluster method as used in many-body theory and the
Wilsonian exact renormalization group. Even though the method is intrinsically
non-perturbative, one can easily implement a loop expansion within it. In this
letter we provide further support for this aspect of our formalism by obtaining
results for the two-loop renormalized $\phi^{4}$ theory. We show that the
non-unitary representation inherent in our method leads to an economic
computation and does not produce any non-hermiticity in the relevant terms.
