How to decrypt a file at a time that has been encrypted in chunks (AES GCM)

Question

for AES GCM encryption, I use the standard crypto/cipher package, the file arrives over the network in chunk of 5 megabytes, each chunk is encrypted with one key and one nonce. The encrypted chunk is added to the shared file. You need to be able to decrypt the file in one call to the Decrypt() function (not decrypt the file in blocks of 5 megabytes). After studying the materials, I came to the conclusion that this is possible if you learn how to define Galois Counter for each block, the problem is that the crypto/cipher package does not imply the transfer of Galois Counter. Please recommend another package to solve my problem (Go) or tell me if it is possible to solve this problem crypto/cipher but in a different way?