Help with moving nodes from one tag to a new

Hi!

Sorry for the somewhat confusing topic but this is what I'm would like
to accomplish.

When I designed an xml-format some time ago I made a mistake
organizing it like this:
<Root>
   <RandomTag1>data</RandomTag1>
   <RCTest1>data</RCTest1>
   <RCTest2>data</RCTest2>
   <RCTest3>data</RCTest3>
   <FGTest1>data</FGTest1>
   <FGTest2>data</FGTest2>
   <FGTest3>data</FGTest3>
   <RandomTag2>data</RandomTag2>
   <RandomTag3>data</RandomTag3>
</Root>

I would like to use the following organization instead:
<Root>
   <RandomTag1>data</RandomTag1>
   <RC>
       <Test1>data</Test1>
       <Test2>data</Test2>
       <Test3>data</Test3>
   </RC>
   <FG>
       <Test1>data</Test1>
       <Test2>data</Test2>
       <Test3>data</Test3>
   </FG>
   <RandomTag2>data</RandomTag2>
   <RandomTag3>data</RandomTag3>
</Root>

I wonder whether it would be possible to write an xsl transform that
does this particular transformation so I can version check old files
and transform them to the new format for backward compatibility rather
than support reading both the old and the new format in my program.
I'm not looking for some general solution that automatically
understands that RC and FG are two suitable prefix to create a parent
node for, this is something I can specify myself.
I did some initial tests, but I realized that I don't know enough xsl
to do this kind of transformation, but if someone can point me in the
right direction (or perhaps convince me that this kind of transform is
not possible with xsl) I would be very happy.

Regards
/David Larsson