How to have different seeds for random generation in Simulink?

I have a model in Simulink that uses the Random Number block. This Random Number block uses a Seed value for the generation of random values. Now if I have multiple copies of my model:

main.slx
    |
    |-----> child_1.slx (Random Number block inside)
    |
    |
    |-----> child_2.slx (Random Number block inside)
    |
    |
    |-----> child_3.slx (Random Number block inside)

How can I set the Seed of Random Number to be different in each copy?