Well, you said yourself you cant keep them indoors, so it lookes like it has to go outdoors, unless you want to cut it in half, basically top it, but completely in half.

This will obviously decrease the size, and slow the growth down a little from shock, but that way it will work.

Or you can put them outside, and they'll get used to it.

They'll carry on vegging untill fall when they flower, so damn, they could be very big by then so keep an eye on the size.