How do I fix these automatic weights on loose articles/clothing?

I am currently working on a character model, and when I try to apply the armature with automatic weights, they appear to be distributed.. weird. There are a ton of loose parts, but they are all joined into one object. Is there an easy way to solve this problem for all the loose parts, rather than going through every thingy of hair/armor? I'm sorry I'm not really good at modeling and rigging :/