Maybe. Perhaps using the api as mailer and/or transport would work. I have no idea if it would spool differently or if 2 spools could be designated.
Here is the output from the command help
–message-limit=MESSAGE-LIMIT The maximum number of messages to send.
–time-limit=TIME-LIMIT The time limit for sending messages (in seconds).
–recover-timeout=RECOVER-TIMEOUT The timeout for recovering messages that have taken too long to send (in seconds).
–mailer=MAILER The mailer name.
–transport=TRANSPORT The service of the transport to use to send the messages
-h, --help Display this help message
-q, --quiet Do not output any message
-V, --version Display this application version
–ansi Force ANSI output
–no-ansi Disable ANSI output
-n, --no-interaction Do not ask any interactive question
-e, --env=ENV The Environment name. [default: “prod”]
–no-debug Switches off debug mode.
-v|vv|vvv, --verbose Increase the verbosity of messages: 1 for normal output, 2 for more verbose output and 3 for debug
The swiftmailer:spool:send command sends all emails from the spool.