SOAP Email API - Batch Send To Unsubscribes

Hey Code It,

When deploying emails throug the SOAP Email API - it seems as though you're only allowed to send to unsubscribed contacts on a one-off basis.

If I set the AllowSendToUnsubscribed flag to 'True' the deployment will only allow me to send to a single contact ID (instead of an distribution list/contact group). When sending out large batches to unsubscribed contacts, this becomes a pretty long process (several hours for ~5k contacts). Is there anything we can do to deploy an email batch using a contact group while sending to unsubscribed contacts?

Thanks,

Ilya