Show all sims in household's friends and contacts when planning events

When I plan an event I only see the friends and contacts of the sim I have selected currently. 

I would like to invite also friends and contacts of the other sims in the household.... 

Like I have a family of 4; dad, mom, son and daughter. 

The dad and mom don't know all of the son's friends.... so I can't invite all of the son's friends to his birthday party... 

Which is weird, no?....