You can, though this will incur some costs related to temporarily storing your data in S3, as it either won't be immediately transferred when using lifecycle policies, or will incur extra charges if you force a type change based on filesizes and filecount.

Note that there is also a minimum filesize of 128KB per object in Glacier as well as 32KB extra metadata, and everything smaller will also be counted as the minimum size. Some mitigate this by bundling files in larger chunks, at the cost of retrievability and now having to keep an map of file-bundle associations.