  In this work we study the opinion evolution in a community-based population
with intergroup interactions. We address two issues. First, we consider that
such intergroup interactions can be negative with some probability $p$. We
develop a coupled mean-field approximation that still preserves the community
structure and it is able to capture the richness of the results arising from
our Monte Carlo simulations: continuous and discontinuous order-disorder
transitions as well as nonmonotonic ordering for an intermediate community
strength. In the second part, we consider only positive interactions, but with
the presence of inflexible agents holding a minority opinion. We also consider
an indecision noise: a probability $q$ that allows the spontaneous change of
opinions to the neutral state. Our results show that the modular structure
leads to a nonmonotonic global ordering as $q$ increases. This inclination
toward neutrality plays a dual role: a moderated propensity to neutrality helps
the initial minority to become a majority, but this noise-driven opinion
switching becomes less pronounced if the agents are too susceptible to become
neutral.
