Select Session by Key

[Francesco]

Hi everyone,
I need functionality through the custom rules. 

I need a button in the tool menu that allows me to select all those sessions that have a certain word in the url.
I don't want to use the filters because I wouldn't want to touch them. 

I started to do this method: 

public static ToolsAction("Select session")
function doSelect(arrSess: Session[]) {
    var key = FiddlerObject.prompt("select key");
    for (var i: int=0; i<arrSess.Length; i++) {
        if (arrSess[i].uriContains(key)) {
            //do something
            //select session
        }
    }
    MessageBox.Show("Done"+key);
}

but I do not know how to conclude the for cycle. 

but I do not know how to conclude the for cycle. What object should I use to select sessions? 
To give an example, I would like a "Matching Value" feature (see screenshot) that can be customized with the custom word.

Can you help me? 
Francesco