Help me control 2 LED strips's brightness separately with fastled

Firs, thanks for reading my topic
Im making an application with visual studio and one of the functions is to send 2 different numeric data
via serial.
The first one is for setting the brightness for led strip number 1 (CRGB leds1) and the second one is for strip number 2 (CRGB leds2)

The code worked smoothly when I control both strip’s brightness with one value bys using FastLED.setbrightness()
to make them individually controlled, one of them I use ColorFromPalette( …, brightness2);
and one of them I use FastLED.setbrightness(brightness1), but the brightness2 are overided by brightness1

no matter I call ColorFromPalette( …, brightness2); before or after FastLED.setbrightness(brightness1)
please help
thanks

void setup()
{
Serial.begin(1000000);
} 
void loop()
{
for (int i = 0; i < 100 0; i++)
    {
      if (Serial.readBytes((char*)buffer, 3) < 3) return;
      if (ledNum < NUM_LEDS)
      {
        if(i==0)
        {
           brightness1 = buffer[0];
           brightness2= buffer[1];
           mode=buffer[3];
}
     else
{

        blue = buffer[0];
        green = buffer[1];
        red = buffer[2];


        }
}
leds1[i]=CRGB(re,green,blue);
FastLED.setbrightness(brightness1)
leds2[i]= ColorFromPalette( currentPalette, colorIndex3 + sin8(i * (50-sincounter)), brightness2);
FastLED.show()
}

Have a look at this webpage, read it all. I think what you want is the last example, but read the whole page as it shows several ways of using multiples led strips

Thank you so much.
I've read and use all of them but the last one
fool me
I wil test it and I will tell you what happen