Hi,
Sure, should be possible.
Take a look at credit card pattern (basic). Make a cutom copy of it and within the "\b" word boundaries add "(" and ")" and a {min,max} repitition quantifier.
Should look like: \b((\<!-....(?!-)){2,}\b
Create a Content rule where part of message matches your custom pattern.
For testing purpose i would add a second clause like a special word withing the subject.
Regards
Thomas