Removing Duplication from Regular Expression String declaratio in Java

The following regex is used to extract hex values from a .cap file.

final String theRegex = "[a-f0-9]{4}:\\s[a-f0-9]{2}\\([a-f0-9}{2}\\s)?([a-f0-9}{2}\\s)?([a-f0-9}{2}\\s)?([a-f0-9}{2}\\s)?; ...etc.

There appears to be a pattern

([a-f0-9}{2}\\s)?

but how can you improve readability?