That's like...the Ultra-ga-zillion, ba-million, quadrillion, snizillion, dollar question.
Sadly, the answer to this bewildering question is unkown.
There only exists one set that 'was' on Teenfuns (before I joined) and apparently will no longer appear.
GS stated once, but long ago, that: "Uma has a very jealous boyfriend
"
So, the world may never know the real truth.