Filter in marketo that pulls in related contacts from an account
Does anyone know of a particular filter or a way to use filters in a smart list to pull related contacts associated with an account? I can't seem to find a filter that digs into this. I am using the "Has Opportunity" filter and "Has Opportunity Product" filters, and they are pulling in some of the people I need, but have since found that we have some of our opportunities that don't have a contact on them, and therefore they aren't pulling them in.
Any help/guidance is appreciated.
Thanks.