Filter built-in list based on contact's account and related connections

Question

I have a list which contains various items belonging to an Account. I have contacts which by default can only belong to an Account. This works well, for example the default Company Name look-up field which is a many to one relationship to Account, if I add the account name only the items within that account shows up (account related to the logged in contact). This filtering in the list is set via the Filter Conditions of Account Attribute.

What I want to achieve is for a contact to be part of multiple accounts and having the ability to filter the list both on the primary set account and the rest of the contact connections. So in theory, via Connections (opted for this since I heard is better than N:N relationship) the contact is part of multiple accounts but the questions is how to filter the list to reflect the account items which contain the contact's primary account as well as its connections ?