Pumping for another baby (not my own)

Rhianna1981

I have a 3 1/2 month old daughter, who is exclusively breastfed (she won't even take a bottle). I am donating my frozen stash to a local wounded warrior family, but I would really like to be able to continue pumping and donating to this baby, since I know that they need the milk. (And honestly, I figure that it is the least I can do for a family who has gone to war and been injured for the collective "us".)

My question is this: What is the best way to go about pumping for this other baby without producing an oversupply? Or, do I actually WANT to create an oversupply? I know that I won't be able to provide enough milk for this baby to be exclusively breastfed, and I am okay with that-- but I would like to do what I can. Should I aim to pump a certain number of ounces per day or what? 

Thanks.