issue-34 example

Given the following LD.

<Person/1>
   :friend <Person/7>, <Person/9>
   :enemy <Person/6>

Issue-34 says it needs a simple way of linking a new friend (<Person/4>), to end up with

<Person/1>
   :friend <Person/7>, <Person/9>, <Person/4>
   :enemy <Person/6>

? 

So, I believe that aggregation is an essential piece for lDP. 

regards, 
Roger