It is possible.
create you combilist.
split the list into 2 parts of the same size
run in terminal1
wlangenpmkocl -I part1 -a plainmasterkeylist1 -P 0 -D 0
run in terminal2
wlangenpmkocl -I part2 -a plainmasterkeylist2 -P 0 -D 1
if both threads finished:
cat plainmasterkeylist1 plainmasterkeylist2 > totallist
create you combilist.
split the list into 2 parts of the same size
run in terminal1
wlangenpmkocl -I part1 -a plainmasterkeylist1 -P 0 -D 0
run in terminal2
wlangenpmkocl -I part2 -a plainmasterkeylist2 -P 0 -D 1
if both threads finished:
cat plainmasterkeylist1 plainmasterkeylist2 > totallist