Software Distribution:How should I exclude few clients in the same collection

Hi,

I was asked to distribute the software to a collection consists of 100 clients, but out of 100 I need the Software to be distributed to 90 machines, which means rest of the 10 machines should not receive the software.  Condition is that I should not create any new collection for rest of 10 machines.  

Would be of great help if any one can guide me how to achieve this.

Thanks in advance.