Aurea bamboo division

Can I divide a clump of Aurea bamboo now?
I've just received a large bare root clump that was despatched on Thursday & arrived today- roots still damp in plastic bag.
I am going to plant it in a plastic cold water tank/cistern that came out of the loft. Have drilled drainage holes in the bottom of the tank & filled the the base with old concrete rubble to give it a bit of weight as I've set it in the ground with 6" above ground in case of runners.
The tank is approx 3ft wide & would look better with 2 smaller clumps.
Any ideas?

 

Yep divide it if you want. I've found the use of reciprocating saw the easiest way to do 'divisions'