It would not qualify.

Well in that case, I was not talking about group selection. I was referring to a set of individuals each of whose reproductive fitness would be enhanced by the beliefs shared by him and the other members of the set of individuals.

I think that in normal discussions, it's reasonable to refer to a set of individuals with shared beliefs as a "group." And if those beliefs generally enhance the reproduction of the individuals in that group, it's reasonable to state that the reproductive fitness in the group has been enhanced.

Try to avoid it.

I suppose, but I think it was pretty clear from the context what I meant when I said that certain beliefs "arguably increase the reproductive fitness in the individuals and groups who hold them." At a minimum, I think I deserve the benefit of the doubt.