Hey there @nicotolsta , welcome to this lovely community
So like @Liz is saying, this currently cannot be achieved with the native Typeform - Mailchimp integration. If you’re not completely against introducing a third-party to the scenario, you could check out Integromat.
Thinking about it, I am now remembering that I posted a way of achieving something similar over here several weeks ago. The use case is not exactly the same but the main thingie here - setting up conditional logic - remains the same. Integromat has an in-built system of filters and functions that helps you manipulate your data in any way you like 
if you’d like to learn more about filtering in Integromat, you can check out this tutorial:
Good luck with this!