List of Object String. Please Help

Dear All, 

I have a list of of object, of which have a properties named Category and Used.... like so....

object1.category = "customer" 

object1.used = "true" 

object2.category = "customer" 

object2.used= "true" 

object3.category = "Accounts" 

object3.used= "true" 

object4.category = "Accounts" 

object4.used= "false" 

object5.category = "Dispatch" 

object5.used= "false" 

object6.category = "Dispatch" 

object6.used= "false" 

I am wanting to search the list and for each category, if all properties "Used" are set to true , then carry out some code....

any help would be greatly appreciated

james