Four of my favorite sims lived in a fraternity house in the university expansion pack.  One of them had just graduated but was still on the lot (since the game allows them to stay for 3 days after they graduate) and I decided to send the whole household on vacation to celebrate that sims' graduation before she had to move out.

Since none of the sims owned vacation properties, I sent them to Potterhouse Bungalows on Twikki Island.  At first everything was fine, but then one of my sims wanted to go on an outing with another.  So I had them have an outing at one of the community lots.  When they returned, I could control them, but the other two sims in the household became "guests" and I couldn't control their actions.

I knew something was wrong so I immediately called the shuttle to take them back home.   They got into the shuttle ok, but then instead of returning back to their university frat house, I suddenly got a screen that the game was loading a household in Pleasantview, owned by the graduating sim's sister.  The sister used to live with them in the frat house until she graduated and moved back to Pleasantview.  

Except when the game finished loading, it loaded the vacation house that the sister sim owned in Takemizu Village!   And when it loaded, it was only in buy/build mode.

I left without saving but when I went back to the university, the game said that the household is still on a lot in Takemizu Village and would I like to play that lot.  When I do, it only appears in build/buy mode.

My sims are stuck between the vacation home that they weren't supposed to be in and their fraternity house!!!

I've tried bulldozing lots, moving lots, packaging lots and none of it works because it says there's a game saved on the lot.   I've tried inviting the missing sims to friends' houses but they are unable to move in with them.  I even tried killing them at friends houses, but they cannot be killed.  

I don't know what to do!  4 of my favorite sims that I've played since they were children are missing in the netherworld!

Some have suggested using summoning objects or the insiminetator to summon sims and then ask them to join the household but I can't find exact instructions anywhere!

Could anyone help me get my sims back?!  If you suggest using any summoning objects, could you let me know step by step how to install them and use them.  I downloaded one and unzipped it but it doesn't appear anywhere in the game.  

Thank you! :smt120