Multiple regions/signature in i.class

[IBH7CAB at MVS.OAC.UCLA.EDU]

I have been experimenting with i.class to perform a supervised
classification of a SPOT image.  Could someone please tell me if
it is possible to define multiple regions for a single
information class (or signature)?  I would like to identify
agricultural fields planted in particular crops and some of these
are relatively small.  Therefore, I would like to build a signature
around several training sites in order to increase my
sample of DNs for each class.  Thanks in advance!