how to design high power LED light circuit,

I am new to electronics, want to prototype a LED light with 3 red led, 3 blue led and 3 white led. All the led are 1W high power LED. Each group of color can be controllable respectively and I want to change each group of color intensity through PWM.

I am using one arduino uno board, I have some questions about the design of this circuit

1. so it is likely I need to use 3 PWM ports to control all three groups of LED, but since I have some other devices to link to the PWM pin, is it possible that I use 1 PWM pin to act like 3 PWM, any chips needed in between arduino and LEDS.

2. and because it is high power led, how can I decide the right current regulator in between the LED and arduino.