MC is pretty much globally applied to a particular device
type. At the transistor level there is no lower hierarchy,
the spectre stop-view is found and that's it. Unless you
add views to the stop-list, from which the hierarchy
editor can choose.
For example you might make a cmos.sch view under
your favorite library nmos device, and attach it to a
Spectre model where all of the variables' sigma terms
are zeroed / made unity (adder or multiplier, variously).
That would mean messing with CDFs and of course
access to the lower levels of the PDK would be needed.