Possible to add many groups to contact during group assignment upload?

Hi Phoebe - The Group Assignment Upload does not support what you are describing. Each specific assignment for a given constituent must have its own row. I would imagine (this is speculation, and perhaps someone who actually pulls offline data for the upload can elaborate) that most clients therefore extract this info out of their system by group as opposed to by constituent. For example, pull everyone in the major donors group one row at a time, or pull everyone in the volunteers group, as opposed to by constituent where all that person's groups might be extracted on a single row.