Which VCF field do I use to specify a group in Android? And how do I get the picture via URL?
Here's a list of valid VCard fields separated into supported/unsupported by Android's vcard importer:  

VCardConstants.java

It currently (4.3) says, ORG is supported while CATEGORIES is not. Check it yourself for more clarification.
You may also want to compare what has changed in 4.0/4.1/4.2/4.3 here.