Redirect to specific thank you pages

We have a landing page that collects email addresses for a specific campaign and we also have a sign up bar the pops open one every other pages that collects generic email subscriptions to a mailing list.

What we would like to do is redirect people to different thank you pages once they have completed the form.

Currently there is an option to redirect people but only to one page and I hope there is some kind of hook we can use to change this default functionality?

Many thanks!

https://wordpress.org/plugins/wysija-newsletters/