It would indicate that these are shared UV's...I could be wrong. I have a lot of trouble lately with my UV editor...it does strange things...sometimes I cannot select edges etc. Try selecting ONE UV on the part you want, RMB then a pop up will appear, go SELECT>SHELL and see if this sorts it out. I use it quite a bit myself.
cheers bullet
bullet1968
"A Darkness at Sethanon", a book I aspire to model some of the charcters and scenes