I would like to ask a question about automorphisms of free products of groups. More specifically, let $G = G_1 \ast ... \ G_n \ast F_r$ where $F_r$ is free group on r generators. We can define the group $Out(G)$ of outer automorphisms of $G$, as the quotient of automorphisms with the inner automorphisms.
Then we can see as a subgroup of $Out(G)$, the automorphisms that have a representative $\phi$ from $G$ to $G$, which induce the identity on $G_i$'s and restricted to $F_r$ is an automorphism from $F_r$ to $F_r$. My question is if this subgroup shares any properties with $Out(F_r)$, for example can we say that this subgroup is virtually torsion free or maybe every torsion subgroup is finite?
Thanks a lot in advance for your time.