How to ignore file names with spaces

Can some help please. I am renaming files to include a spaces at two different locations. This I have no problem with. But there are hundreds of files and some already have the spaces so I don't want extra space added to those file names. Is there a way to do this.

Thanks

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Reply to #1:
Yes there is, with regular expressions, but you would need to explain and give a few examples of where the spaces go

cheers

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Reply to #2:
Ok. Sorry.
Filenames are in this format XXXXXXXXXXXX. I can get them into this format with no problem XXXX XXX XXXXX (Spaces added at position 5 and position 8)
What I need to do is ignore any filename that are already in this format XXXX XXX XXXXX so that more spaces are not added.

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Reply to #3:
method: replace
text to be replaced: (.{4})\s?(.{3})\s?(.{5})
replace with: \1 \2 \3
use regular expression: checked

there you go

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