Of course you own them so you can do what you want. BUT
I'm for not splitting them up. They may be nearly-identical
but part of the appeal of gengas is the process. That is,
one can see the process of animation and see many different
hands working on them.

Please do not set the precedent so that others might start
taking apart and selling the sets they buy. It's a bad idea and
as a genga collector, I find the sets much more valuable 
(personally and economically) than a single sheet.

Just my opinion,

Wendy