script in root prim changing other prims' param

i'm using the following script for auto sensing daylight in outdoor lighting.

I need help altering this script so that it can effect a group of linked prims. I assume this would be easier on the client rather than having 8 identical scripts in all 8 prims...

i do not know how to setup a script to talk to other prims in a link.

thank you in advance,
Lefty

---------------------------------------------------------
// v0.0.4 - uses the new llSetPrimitiveParams() call to disable client light rendering when off!

float fTime = 0;
float fDayThresh = 0.66;
float fNightThresh = 3.46;
integer iTimerSecs = 300;
string sOutPre;

init()
{
sOutPre = llGetScriptName() + ": ";

refresh();
llSetTimerEvent(iTimerSecs);

llWhisper(0, sOutPre + (string)fTime + ": startup...";
llWhisper(0, "Timer interval is: " + (string)iTimerSecs + " seconds.";
}

refresh()
{
fTime = llGetTimeOfDay() / 3600.0;
}

set_light(integer iOn)
{
if (iOn == TRUE)
{
llSetPrimitiveParams( [PRIM_MATERIAL, PRIM_MATERIAL_LIGHT] );
}
else
{
llSetPrimitiveParams( [PRIM_MATERIAL, PRIM_MATERIAL_GLASS] );
}
}

integer IsDay(float fTimeOfDay)
{
integer iDay;

if ( fTimeOfDay > fDayThresh && fTimeOfDay < fNightThresh )
{
iDay = TRUE;
}
else
{
iDay = FALSE;
}

return iDay;
}

default
{
state_entry()
{
init();
if ( IsDay(fTime) )
{
state Day;
}
else
{
state Night;
}
}
}

state Day
{
state_entry()
{
refresh();
set_light( FALSE );
}

timer()
{
refresh();
if ( !IsDay(fTime) )
{
state Night;
}
}
}

state Night
{
state_entry()
{
refresh();
set_light( TRUE );
}

timer()
{
refresh();

if ( IsDay(fTime) )
{
state Day;
}
}
}
----------------------------------------------------------------

Unfortunately, no llSetLinkMaterial exists. Your best bets are llSetLinkAlpha and llSetLinkColor, otherwise you're going to need a script in every prim.