  Let $M$ be a monoid and $G:\mathbf{Mon} \to \mathbf{Grp}$ be the group
completion functor from monoids to groups. Given a collection $\mathcal{X}$ of
submonoids of $M$ and for each $N\in \mathcal{X}$ a collection $\mathcal{Y}_N$
of subgroups of $G(N)$, we construct a model structure on the category of
$M$-spaces and $M$-equivariant maps, called the $(\mathcal X,\mathcal Y)$-model
structure, in which weak equivalences and fibrations are induced from the
standard $\mathcal{Y}_N$-model structures on $G(N)$-spaces for all $N\in
\mathcal{X}$. We also show that for a pair of collections
$(\mathcal{X},\mathcal{Y})$ there is a small category ${\mathbf
O}_{(\mathcal{X},\mathcal{Y})}$ whose objects are $M$-spaces $M\times_NG(N)/H$
for each $N\in \mathcal X$ and $H\in \mathcal Y_N$ and morphisms are
$M$-equivariant maps, such that the $(\mathcal X,\mathcal Y)$-model structure
on the category of $M$-spaces is Quillen equivalent to the projective model
structure on the category of contravariant ${\mathbf
O}_{(\mathcal{X},\mathcal{Y})}$-diagrams of spaces.
