I need to know if it is possible to define independent policies on SMG for each local/hosted domains?
Not for some things like IP Reputation and Sender Auth. You could use Policy Groups to create per-domain policy groups where membership was defined by the domain. You would create policy group per domain and use *@domain.com to define the members.
You would then define the Spam, Virus, Content policies you need, and assign them to the approprate Policy Group.
Thanks for the feedback. I will check this tomorrow and confirm back here.