Link Message in Link Message

I was hours last night tracing an inexplicable bug. Because of the system down for maintainance, I can't write a simple test to demonstrate the problem, but I'll describe it and see if anyone knows a solution.

Script A is responding to a message sent via "llMessageLinked( LINK_THIS" from Script B and works flawlessly. Script B sent the message under conditions arising from a timer event. Script B was expanded to respond to a link message from script C that triggered the message to A (hence over-riding the timer). And at this point, things got very weird.

It seems that, when processing the message in script A, the script would do a 'return' at an arbitrary point in the code. In sheer frustration, I put in:
llOwnerSay( "A" );
llOwnerSay( "B" );
llOwnerSay( "C" );
llOwnerSay( "D" );
llOwnerSay( "E" );

And as out put, I would get A,B,C and nothing further. Sometimes A. Or A,B,C,D.

As far as I could tell (before I dragged my weary ass to bed), if one script sends a link message to second, and the second in turn sends a message to a third, then the third script is forced to return at the same time the second script returns.

In anyone's experience, is this correct?
Is this a bug?
Is this by design?
Is there a sensible workaround?

The problem is that all scripts will respond to all link messages. So when the first script sends a message to the second, the third gets this also. The only way to avoid this is to put each script into seperate prims of a linked set, set send your link messages explicitly to the prim containing the script desired. I ran into this myself recently.

Something that might help make your life a little easier is identifying all of your link messages with a 'key' of sorts...

...if I have a one-prim object with multiple scripts (I have a couple items I sell that have between 2 and 6 scripts in a prim), then I'll do something like the following:

Script 1:

integer SEND = 23;
integer RECEIVE = 24;

default
{
    touch_start(integer num)
    {
          llMessageLinked(0, SEND, "Hello Script 2", NULL_KEY);
     }
    link_message(integer sender, integer int, string str, key id)
    {
         if(int == RECEIVE) //do stuff
    }
}

Script 2:

integer SEND = 24;
integer RECEIVE = 23;

default
{
    touch_start(integer num)
    {
          llMessageLinked(0, SEND, "Hello Script 1", NULL_KEY);
     }
     link_message(integer sender, integer int, string str, key id)
    {
         if(int == RECEIVE) //do stuff
    }
}