It seems to be working for me. Here's what I did to get it to work:
1. Open cheat console in Live Mode, on pause.
2. Copy and paste (Ctrl+V) the cheat: relationship.introduce_sim_to_all_others into the cheat console.
3. To check to see if it worked, click on relationship to see that they know everyone.
4. Repeat the above steps for each Sim in household.
With doing this, your game may have some lag due to your Sim knowing everyone. Basically the game adds more entries to the database, making it bigger therefore causing the lag.