It should come up as one large miner, the hash amount should double with 2 pacs or triple with 3.
When you start having more than 1 or 2 2Pac, you may need to invest in an external USB HUB. My Dell desktop can handle two 2Pac even at 200Mhz without the USB stick dying most times... But soon as I added three, I had to go to an external USB Hub like Unplugable USB 2.0 7-port "60W" Hub. Running 6 now and it is definitely not 6x the hash rate. You have to get them to hash reliably and it is tricky to get them to all play nicely and zombie out.
I ended up using multipool.us because they give you the coins and don't handle crypto conversion. I keep reading some people losing 20%+ on zpool payouts, so I'm hesitant to use zpool ever.