The original SEM had two input connectors, neither SEM V nor V2 have one let alone two.
It would be great if V2 had a stereo input which you could use in place of the built-in sub OSC and the noise generator. A switch could decide if you want the mono sum of the input replace either the sub OSC or the noise generator - or if left and right channel replace both built-in SEM "add-ons". So you could use the plugin really as an expansion module as its name implies.
Masi