How can I activate the MailChimp Integration plugin for individual sites on a Multisite setup

Hello team!

I am looking to add the MailChimp integration plugin for a client and noticed that I can only network activate with one API key, so I'm guessing that it would be for someone who wants to sign up to the newsletter of the whole network.

Is there a way to activate on a single site basis, for one or multiple clients?

Thanks in advance for your support,