Hello, I've been wracking my brain over this...

I have a document typed in all caps (the font is formatted in all caps) and I need to find a way to convert all the text within brackets to sentence case. After much digging, I found the way to convert all the bracketed text to lowercase, but I really need the first letter of each text within those brackets to be capitalized. For example, it needs to look like this:

THIS TEXT CAN STAY IN ALL CAPS. [But this text needs to be in sentence case]

When I look through all the options in the Find/Replace I don't see anything that lets me choose "sentence case". So I'm wondering if there is a step two that is necessary in order to take all the bracketed text and convert it to sentence case. But how would I do that? Can I create a macro or command that takes every character immediately preceded by a [ and changes it to a capital letter? Any help or ideas would be greatly appreciated. Thank you!