TimeQuest Timing Analyzer

Well, actually, I've designed a Ling adder well known for its good performance.

Now, I have another question: my system has four clocks: a source clock and three clocks derived from it. When I run the TimeQuest timing analyzer and check the fmax summary, it displays all the clocks. My objective is to improve one of the three clocks only. I don't care about the two others. So, I guess Quartus is trying to improve both frequencies and is selecting the best agreement. How can I tell Quartus to focuse on one clock only ? By adding a constraint on that clock ? And how ?

Thanks !

Julien