Managing a charity database within Marketo

Our company runs a charitable program, which we have a website for. We would like to use Marketo to email people involved in the program, but need to keep them separate from our "Marketing" database. In some cases the audience are teenagers we are communicating with, so they cannot fall into our normal "Marketing" communications.

I have thought to unsubscribe them, but then they get blocked from communications, and I don't want to change their unsubscribe to false before every email, then change to back to true.

Is there a better way to manage this separate database in Marketo - I do not feel confident telling the marketing team to always exclude this database from Marketing activity, it is likely they could forget to do this.

Thanks