Bulk driven configuration layout

Am a newbie to layout and trying out the electric tool for layout. I am using a
bulk driven configuration in my circuit. How do i do this in electric. When i
use the mocmos library ... all the p-wells are connected to gnd and n-Wells to
vdd irrespective of what signals i give to the well contact.( i need to give
clock to some of the p-wells).  How do i avoid this?? Is there a provision for
using the twin-well process so that this can be avoided. Could not find any
documentation about using the bulk driven configuration in electric.Please Help