How to manage Outlook email based on Contact Groups
Make a distribution list in your contacts and then apply the rule in step one to "from people or distribution list" and choose the distribution list you created.
To create a new distribution list open your contacts and hit ctrl+shift+L, then click select members to add people from your contact list, or add new to add people who aren't in your contact list.
You'll need to create an ingoing and outgoing rule (if you do want your sent items organised the same way) but at least you can administer the rule by groups of contacts rather than a unique rule for each contact.