I don't see a major need for this idea. It makes sense that you might have multiple outputs that you want affected by the same condition, but it can be easily implemented by having multiple conditional terminals, and just have the boolean wire split going to each of them.
This would address some space concerns on the border of the loop if you had multiple -- would keep the tunnels from getting spaced apart, which makes downstream wiring easier. My hesitation is on readability. The sublty between two tunnels close to each other and two tunnels joined to the same condition would be easy to miss when reading a diagram. Still, it seems like an idea worthy of exploration. I'll chip in my kudos for "this or something similar".
If you are thinking of something simmilar.... a possible implementation might be to output that "Multi-Terminal" as an array of clusters rolling in the "index and bundle" or "Build Cluster Array" functions as appropriate and NOT limiting it to conditional tunnels at all. If the data is that closely related it probably should be in a cluster anyhow and, a "Multi-Terminal" doing the bundling or unbundling automagically would hide the bundle / unbundle code that is usually rather unimportant for the BD space it takes. "Oh, that's a bundle unbundle tunnel" kind of floats over the tounge when you say it.
