Tested:

    parallel -S'ssh -oProxyJump=nlv.pi.dk,,64gw nlv.pi.dk' ::: hostname

Convert this to generic names but keep ",,"

    Using password or SSHPASS with --(n)onall exposes the password on the command line, making it visible to local users via ps.

Test this works.

    SSHPASS=foo
    parallel myuser:@host

[@hostgroups/][ncpus/][[user][:[password]]@]host[:port][,...]

@hostgroups - one or more groups this sshlogin belongs to. Multiple groups are separated by '+' (See --hostgroup). Examples: prod, dev+remote

user - user to log in as. Defaults to the current user name. Examples: alice, bob

:password - use password for authentication. If password is omitted use $SSHPASS. If : is omitted use ssh's default authentication. Examples: :mypassword, :

host - hostname or IP address of server. Examples: server01, 10.1.2.3, [2001:470:142:4::a], 2001:470:142:5::116. Ranges of hostnames can be given in [] like this: server[1,3,8-10] (for server1, server3, server8, server9, server10) or server[001,003,008-010] (for server001, server003, server008, server009, server010). With Bash's brace expansion you can do: -S{dev,prod}[001-100] to get -Sdev[001-100] -Sprod[001-100] More [] are allowed: server[1-10].cluster[1-5].example.net

:port - port number to connect to. Examples: :22, :2222. For IPv6 you can use p or # instead of :. Examples: [2001:470:142:4::a]:2222, 2001:470:142:5::116p2222

See --sshloginfile for complete examples.