How do I have platforms only affect some objects?

Hey guys,

Let's say I have 2 sprites and 2 platforms. I would like Sprite 1 to be able to run along Platform 1, and Sprite 2 be able to go on Platform 2, however I don't want Sprite 1 to have collision with Platform 2 and vice versa.

I'm not sure how to achieve this effect so any help is appreciated.

Thank you!

Here's a list of ways:

Thank you!