[SUMA] Masking surface from node indices list

AFNI version info (afni -ver):

I would like to mask V1 and V2 with different labels or values such as 1 and 2 on the individual surface. I could find that FreeSurfer label folder has v1 label files, which contains a node list. I could convert them into 1D and then niml.dset, but binding two V1 and V2 niml.dset files into one niml.dset is quite tricky due to the different node indices between two files. It seems to be easy because it was not for me. plz help me.

==== What I tried =====

awk 'NR>2 {print $1}' lh.V1_exvivo.label > lh.V1_exvivo.1D
awk 'NR>2 {print $1}' lh.V2_exvivo.label > lh.V1=2_exvivo.1D

ConvertDset -n_mask lh.V1_exvivo.1D -input {cortex_masked_niml.dset_file} -prefix lh.V1_masked.niml.dset
ConvertDset -n_mask lh.V2_exvivo.1D -input {cortex_masked_niml.dset_file} -prefix lh.V2_masked.niml.dset

3dcalc -a lh.V1_masked.niml.dset -b lh.V2_masked.niml.dse -expr "a+2*b" -prefix lh.V12_masked.niml.dset

==> it yielded an error due to the different vertices.