down the bottom of the UV unwrap window there's a button with a triangle on it. It's next to the lock selection button. This is the filter selected faces button. If you select some faces in the viewport, and then hit this button, it will hide the other faces.
The easiest way would be to stop using seams! Select edges and 'break' them, then use peel/relax. Wtf are seams for anyway? that useless pelt function?
you can select faces in the uv editor and then right click and hit break. it creates map seams (the green ones). pelting will do this for you, only difference is you cant use the edit seams functions on map seams
You can assign various faces to different material IDs and then use the ID selection box in the UVW Unwrap window to toggle different material ID groups on and off. If have never used this feature - I simply separate my object into logical sections and unwrap each by itself. Once a piece is unwrapped, I drag it off to the…