Format in Excel constant

[RobCQM]

We import what are called mac addresses, some are continuous alpha, numerical text and other are formatted we would like the input to be constant in the following format;   18:1B:7E:8G:98:39

six groups of 2 separated by  :  (colon). Any help appreciated.

[#2]

@RobCQM 

A formula solution to consider. Presuming there's a MAC address in A1 for example:

=TEXTJOIN(":",,MID(A1,SEQUENCE(6,,1,2),2))