If there is space between the tunnels you can set up hitting screens to add stations. Also, you could add either bunting ontside of a tunnel with front toss, or even use a light flite machine. Also, it might be possible to set up stations on the outside of one of the tunnels hitting into the net. That would give you up to six stations.
Amy - I think this is why - Breaking them up would be better -
It would still be the same two hour practice but they would only get one hour per group - But since there wouldn’t be (As Many) Girls in each other’s way you could get more hands on training and it's a whole lot easier dealing with 6 in that confined space than trying to work around 12.