See Design Pattern: DRY, How Not to Repeat Yourself in Rules DSL for a collection of techniques that may help. The big challenge here though is that you are using a Channl trigger instead of an Item so a lot of the tools in that post will not be available.
I don’t know much about Hue. Is it possible to link this to an Item somehow? If so then the answer is easy, just apply the Associated Items DP and How to structure a Rule DP.
If not, you will have to create a separate Rule for each Dimmer and then put the code in a lambda (Lambda Example with Copious Notes).
All of the DPs mentioned are linked to from the DRY DP.