There's not a way to filter out by use of multiple periods – at least no in-app method that I'm aware of. You would need to enter a specific domain.
What is possible – and you might already be aware of this, but just in case you're not – is to create an active list by navigating to the Main menu > Contacts > Lists > Create list > Contact-based > and creating an Active List based on Email domain. You'll find this property under the Contact properties. What you can do then is take the list of freemail domians that HubSpot provides in this Knowledge Base article, and paste these values into the field, remembering to separate by using a semicolon. If there are specific domains you'd like to allow, you can always remove them from the list, but this would be the only way of filtering out domains.
Thanks Brian. I have actually done that already. It's the pesky Gmail accounts that are cluttering my Hubspot account and driving me crazy. It'd be great of there was an option to fliter list by a charcter type or something similar. I'm sure I'm not the only person with this issue.