Rhino Tool Advice - Likely Simple

Hi there, I am fairly new to Rhino and CAD in general,

I am trying to do something what I expect is probably a couple of clicks to do.

I am connecting some pipes which are geometrically cut to fit correctly, now I can use the split tool and cut the corresponding shape out of the central post like this

However, I do not want to do that, I simply want to mark the outline of the cut from the 2 connecting pipes, so when I unroll the surface, the mark is there but the cut is not

Like this

This photo shows the unrolled version with a cut, however I would just like the outline of that cut to be there rather than the actual cut

Could anyone suggest what tool would be best?

Hi Matt - DupEdge the edges of the cut tubes and include those curves in UnrollSrf.