I have made a simple script in my DEFAULT.BAR that concatenates multiple MPEG-4 files into one by appending them; I use this to "losslessly" (by stream-copying) transform short (e.g. Snapchat / Instagram / Messenger) clips into longer videos. Pretty neat, huh?

Anyways, my script uses %S for parameter, which I found by the Help. Unfortunately, it took me a while to figure out that I'm not supposed to mark the .MP4 files and drag them to the shortcut I've made in my top bar; this way it only takes the first marked file as %S parameter. Fortunately, I soon realized that the right way to go is to mark all the files and then just click my shortcut.
Now, I'm only missing one little thing for perfection. Namely, a way for the "parsing" not to just grab the marked filenames in alphabetic order. Say I have a.mp4, b.mp4 and c.mp4, it would be cool if there was a way to mark "c.mp4", followed by "a.mp4", and last but not least "b".mp4", and then get my concat:ed output to be made in this order.
Right now it doesn't matter which way I select the files, it ends up merging them alphabetically. I'm guessing this is due to the very core nature of how Total Commander works, which is maybe hard to get by, but I'm just throwing in a Hail Mary pitch here, maybe someone has a delicate but relatively easy solution to solve my issue, perhaps some Single button %parameter that I'm not aware of, that could help me?
Cheers!