adverb
Used when actions or states apply to each member of a group one by one, rather than collectively.
問題は個々に検討する必要がある。
Each problem needs to be examined individually.
部品を個々に包装してください。
Please wrap the parts separately.
別々に means 'separately' in the sense of not together, often for physical separation. 個々に focuses on individual handling within a group.
Compound of 個々 (koko, 'individual, one by one') + adverbial particle に (ni). 個々 is a reduplication of 個 (ko, 'individual, item').