To do this you will need an enclosed coat hanger, some sturdy string, and scissors. Tie the string on one end of the hanger, and then wrap it multiple times around the hanger. At each end, wrap once around the hanger to make sure the strings stay in place and don't just slip off. Then when you have a few layers of the string, tie the end with a few knots and cut it off. This way each piece of the extension will have its own space, you won't have to clip multiple wefts onto one string.
And voila! Extension hanger extraordinaire! You could even cover this with a duster bag, the kind you get at the dry cleaners, but I don't have one.