Is belt lengthening possible?

First time post, I tried searching for this sort of thing here and elsewhere with no such luck. I usually try to match my belts to my shoes quite exactly, to the point of having almost one belt per shoe. However, most recently, my waistline has become more "mature". Now, I have a bunch of rather pricey belts that are 4 inches too short, and I have shoes that I don't like to wear without the matching belt.

Does anyone know of a classy way to lengthen a belt, preferably in some hidden or sneaky way that does not show ( I can't imagine one myself )?