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.
An IDE is no substitute for an Intelligent Developer.