I think Doomsday's got the right method, that's pretty nifty, nice and clean too.

Unroken, sorry, I missed your mention of the shear tool, I must have skimmed over that. I use 2.5 regularly, but not for modeling, [haven't done any modeling in Blender since 2.45 or so, which I was using regularly up until last fall] 2.5 just did my head in trying to figure out how to get the loop cut working!

Were if not for the tool Doomsday pointed out, I maintain shear tool would be the way to go, those other loops, as much as I can tell from the images supplied, aren't relevant to anything, so you could...

a] add them after you did the shear [probably what i'd do]

b] you can just use the shear tool once on each loop so that they're clear of the last loop [what I did below].

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