I don't think so. There are some patches pending for update-account
command that might make this possible over SSH, but these are still
going through the code review process and aren't yet in a release
version.
In the past I have done this using direct SQL to modify the
account_group_members table. After that database change is done, use
`gerrit flush-caches --cache accounts` to force the running server to
reload this table.