Yes of course, just make sure that if you are adding berries you keep the measurements the same, so you don’t end up with overflow. Something else to remember when adding in a variety of berries is that most other berries are sweeter than raspberries, so if you are adding, for example, strawberries or blueberries, you will want to cut down your sugar by ¼ cup so as not to make your pie overly sweet. And don’t feel confined to adding just berries. Apples go great with raspberries, and if you are feeling extra ambitious, even some sweet, juicy peaches can be thrown in.