There are two completely different issues here. One is using [OrigTitle] to record the original title of a film, and [Title] for how you want to refer to it in your database—which may include naming members of a series so they appear together in chronological order. The other issue is about naming files and configuring the file scanner so files are properly matched to the movie records.
The first issue can be dealt with two ways. The obvious one is to use [Title] as it is intended—to name the movie whatever is most meaningful and convenient to you. That can include using the form [Series] # [Episode] even if the original titles (recorded in [OrigTitle]) are not even close to that. The other method is to use a [Movie Series] field to record the series, which can then be used to group the episodes even if they're not similar. I recommend using both. Having a method of grouping the series means you don't have to struggle with dilemma of prefacing a title with a series name when you (or others) may still expect to find it under it's original name. If you look at how I've handled different series in the screenshot, you'll understand what I'm getting at. (My List title format is Title (Year) Movie Series—so I'm reminded of the series even if the episodes are not grouped.)
Important note: I've used the otherwise unused standard [Release] field as my [Movie Series] field (I've renamed it in the UI language file). That has the advantage of having some characteristics a custom field would not—like the context menu (shown) and being a standard search category.
I recommend doing some research before deciding what needs to be done about the second issue. The file scanner default configuration has sample regex for matching some common file naming patterns. Your file names have to contain the necessary data in a recognizable and consistent pattern. Regex that recognize the pattern used must then be added in the right order (they're processed until a match is found). So for the scanner to work properly, you have to either change the filenames so they're recognized by the regex, or change the regex to they recognize the filenames. You can find helpful topics here by searching for 'regex' or 'regular expressions.'
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