MRT - How to rename part of a variable in filename?

[Vlayke]

I have the following situation.
Filename is in format:

name.name.YYYY.DD.MM.name.name.ext

I would like to rename it to the following format:

name.name.YYYY-DD-MM.name.name.ext

My problem is that I'm unable to provide a filter that would select just the two "." characters in the YYYY.DD.MM to change them to "-" characters.

Can you provide any help?
Thanks

[white]

Search for: (\d\d\d\d)\.(\d\d)\.(\d\d)
Replace with: $1-$2-$3

☑ Regex