Hello,
Your configuration is similar to ours & seems to be correct, if placing a 
client with unique saveset in two different groups do not invoke Networker 
to use two drives this is what i suspected also.
One way around is kind of backward and that is to use over the network 
NDMP config ( i belive the cmd is nsrndmp_save -T dump -M -P), i have 
tested this and it does cause multiplexed NDMP save streame, You can also 
use non NDMP Devices for Bkp.

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