Random heights not working after offset

Hello there,

I am trying to make a urban fabric derived from voronoi (first part), and it creates random heights to the houses (second part). Each part works fine.. The thing is that each part works fine, but while mixing both parts together, the random heights became one height..

(In the file I baked the voronoi results and set it into the CRV of the 2nd part and it works fine..)

I guess that I am missimg something that say to each closed curve to be "on its own", though I do not know how to do that...

Any suggestions? 

Regards,

Nankyo.