Any way to merge trimmed surfaces?

Hey all,
As the mergesrf commands only works with untrimmed surfaces, is there any way to merge trimmed surfaces and eliminate the line between them? I am talking about the line that’s visible in Shaded mode. I know there are several threads on this but they’re about 2 years old. Any “secret” command, or not-secret command that is unknown to me, script or python? Anything maybe in V7?
Merge Srf Problem.3dm (46.0 KB)

It’s a little hard to read but it looks like you’re saying “Join the 2 trimmed surfaces first and then run MergeAllCoplanarFaces”. Which I tried and it worked. This is awesome, Martin. Thank you.