Hey Noor, I have an idea on it but it depends a bit on how you use instantly.
If you have 1 campaign that you run everyone through you could duplicate that campaign and assign each domain its own campaign, then as part of your clay set up, you have a "lookup" table which just sorts which domain goes to which campaign, (if it doesn't find it in that table it would pick one at random and if it does find it in that table it uses that campaign) lots of set-up but doable
