Merge end of video to beginning of another

[DynVec]

I'd like to merge the end of video, that is a part of it that begins midway and share the same end, to beginning of another, that is a part of it that share the same beginning but ends midway.

I've make a few searches on FFMPEG on how to do so but I failed. I think I could manage to do it by making the trims, in 2 files, then concatenate them. I'd rather not have a middle-step, meaning those middle-step files either be done automatically (ie by a script) or handled through the OS creating temporary files or, better yet, FFMPEG itself being able to handle the whole thing; the latter perhaps something like

ffmpeg -i "concat:{ ffmpeg -sseof -00:03:30 -i input1.mp4 }|{ ffmpeg -i input2.mp4 -ss 00:01:30 }" -c copy output.mp4

which would make a 5 mins video from the last 3:30 of the 1st and the first 1:30 of the 2nd.

Thank you kindly for your help

[ProWo]

This will not work.
Make your trims and THEN merge with concat.

[Bruce Banner]

This will not work.
Make your trims and THEN merge with concat.

..

[ProWo]

This will not work.
Make your trims and THEN merge with concat.

..

Ok.

[DynVec]

What about

those middle-step files either be done automatically (ie by a script)

? I'm on Windows and have Cygwin installed, so powershell & bash is fine.