Yes. Type "spectre -h montecarlo" and you'll see:
10 ignore=[...] If set, no variation is applied to specified subcircuit instances. In addition, all subcircuits instantiated under this instance do not have variation enabled. By default, mismatch is applied to all subcircuit instances in the design and the process is applied globally.
So you can specify on the montecarlo analysis statement ignore=[I1 I2 I3] etc.