Welcome to the JavaRanch, Avi!
JSF View definitions can contain more than one Form. I often do this.
Backing beans (Models) can exist in a many-to-many relationship with Views.
So there's no general mechanism you can use.
You can use the view binding mechanism to attach a particular UI control to a backing bean. You can then walk up the component tree to see what form it's in. That's not something the average webapp should be doing, though.
The secret of how to be miserable is to constantly expect things are going to happen the way that they are "supposed" to happen.
You can have faith, which carries the understanding that you may be disappointed. Then there's being a willfully-blind idiot, which virtually guarantees it.