Override built-in function?

[vgevolution]

Is it possible, via the plug-in system, to override built-in vbulletin functions, like those in functions.php?

Specifically, every time I apply an upgrade, I have to edit functions.php and tweak the function, "fetch_censored_text", and I add one additional supporting function. This gives me a slightly more robust censor mechanism which has served me well for many years. I can essentially use a replacement word/phrase rather than a character -- and no, I can't do what I'm doing with Replacement Variables.

I've been searching for hours, but haven't found any resource discussing this. If it's not possible, that's fine, but I'd sure love to avoid making function edits every upgrade.

I also end up modifying template.php to accommodate Lynne's awesome code edit detailed here: https://vborg.vbsupport.ru/showthread.php?t=258614

Being able to avoid making those edits over and over would be great. I'm not going to hold my breath, however.