Will the pixel mix audiences from different sites when creating ads?

Question

Facebook

Hello, this is the situation. I have a Facebook pixel, according to the rules 1 per ad account.
I have two sites, different topics. I'm setting up a "Conversion" ad campaign for site A. Will Facebook look at audience selection for those who came from site B? In the Pixel settings, everything is thrown into one pile, and when unloading the retargeting audience, you can select a domain. But with the selection of ad impressions, it’s not clear at all ...