Put the bulbs you want to plant outside in a pot as I describe above. Take a box roughly that size, and remove the bottom and one side of the box's cardboard. Place the pot on the floor (preferably not carpeted) in your cold room snugly against the wall of a warm room. Place the box over the pot so the open side is against the warm room and the top and three sides are exposed to the cold room, the open bottom exposed to the ground floor. So now inside the box the temperature will be between your cold room and warm room temperatures. Hold 1 week, remove the box, hold 1-2 weeks, then plant outside.
I am assuming your ground doesn't freeze more than a few inches down in the winter. You could put the bulbs in the fridge, especially if you plan to grow them in the same pot this summer. But if you are going to plant them out next season anyway, better to do it this winter in your zone 7.
