/streams/ will take a channels parameter, like this:
https://api.twitch.tv/kraken/streams?channel=trick2g,beyondthesummit2,starladder1
It returns one stream object for each active stream. There was someone experiencing some issues when requesting a high number of channels, I believe there is a cap to how many you can put in at once(50, 100 maybe?). To take care of that, you could split up the list into multiple requests.