Sync Gateway - appending user Id to the document Id

Hi,

I’d like to keep the document Ids unique for each user. In the document I pass the userId as a field. Is there a way to append the userId to the documentId in the sync function?

What I mean, is that when storing a document, say docID: ABC_1 for user Id 333 I I want to actually store document ABC_1_333

when I pull that document I want the client to get document ABC_1 – i.e. the user id trimmed.

Can this be done?

Thank you