Can anyone help with a workaround for format masking phone numbers, serial numbers, etc.

Can anyone help me? This seems like a stupid problem but I'm stumped. Our accounting has to have SS numbers formatted with hyphens, but our users do not always enter them. Since creator currently has no input masking functionality (to correct format in user-entered phone numbers, serial numbers, etc), I need a work around.

I've got no problem stripping out hyphens, dots, spaces, etc. to create a clean unpunctuated number, but I just can't figure out how to get the hypnens put in the correct places! There doesn't seem to be a built in function for extracting characters from a string based on their position in a string (1st, 2nd, 3rd). I need to extract the first three characters, then the next two, etc.

Can someone help with this string question or suggest an alternative workaround for the mask?

Thanks a bunch,
Dax