Filtering llListen for more than one Key

I'd like to control a listen event by filtering with llListen so that the script will only respond to one of two people. I know I can't do this .......

llListen(CHAN,"","aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa" | "bbbbbbbb-bbbb-bbbb-bbbb-bbbbbbbbbbbb","START");
CODE

 
but does anyone have a clever idea that DOES work? I know I can always use NULL_KEY and test whatever is passed to the listen event, but is there a way to filter before it's passed? If there is, would that method reduce lag at all, or am I dreaming?

Open two listens, each filtered for the desired av. You can have multilpe listens running together each with its own set of filters.

just use an access List with 2 keys inside or the amount you whant, and then check the user keys into that list , grant access to who is in the list and not if they dont.

list access=["first key","second key"];

key toucher;

//some code to get the key by touch to open a listen event

if(~llListFindList(access, (list)toucher))
{
    do something
    //it exists
    //This works because ~(-1) == 0
    //It saves bytecode and is faster then doing != -1

}

http://wiki.secondlife.com/wiki/LlListFindList

I thought you couldn't have two listen handlers on the same channel. Not true?

nope, i had a poofer that had 3 listens on the same channel, 1 for each command and it worked just fine. (poof, hide, show)

Cool! Problem solved. Thanks!

the benefit of the multiple listens is that the server will filter your listens for you and you can key word filter in the listen at the same time. the drawback is that you have two listens eating server time and they get filtered individually.

the benefit of filtering by key list in the script is you only have one listen and the sim has less to process since it's unfiltered at that end. the drawback is you're script processing time goes up and you'll need to filter key words within the script.

for 2-3 keys I'd go with with multiple listens, for much more than that the internal list checked with if (~llListFindList( gLstAllowed, (list)Id ) probably has less overall impact on the server (unless it's a heavily used channel, then maybe up the changeover limits)

Thanks. That's the sort of advice I was hoping for. I had a gut feeling that it was more efficient to filter with llListen than to use a key list, when I only have two people to listen for. I just couldn't figure how to make it work since I had the mistaken idea that I couldn't have two listen handles on the same channel.