I have had a go at adding an Additional Filter which will filter for records for an individual associated with a specified  person or organisation.  If used for people associated with an individual it doesn't pick up records for that individual, unless they are associated with themselves (which is allowed).

This will need management studio to install. Running the SQL in Management Studio will create a new additional filter called 'Associate (Name or Key)'.  The name entered in the filter must be the Forename,Initials and Surname entered as shown against the individual who has associates. This is without any spaces. For example Fred M. Smith  needs to be entered as FredM.Smith. For Organisations the full name or the Acronym  need to be entered. However, for both Individuals and Organisations 'Starts with' and 'Contains' will work. For example using Contains and entering 'Smith' will find all the entries for anyone associated with anyone named Smith.  'Starts With' could be useful for Organisations with long names.   The key can also be used. This can be obtained from the Name and  Addresses screen using the 'I' button and can be pasted into the filter.

My mistake - and I didn't choose a good example to test it on. The attached should fix it. I have alo updated the original for anyone else  who would like to try it.