This request is used to send more than one message with one call. The required parameters are as follows:

* TemplateId - the id of the template to be sent
* RcptToList - array of recipients' email addresses
* MessageIdList - array of message id per corresponding email recipient 
* ParamsList - array of parameters' values per corresponding email recipient 

The lenght of these lists must be equal. If there is no parameter on the template, ParamList must be set to null value.

MessageId's in MessageIdList are required to prevent multiple sends to the same recipients. So please be aware that if you set the same MessageId when you are using this function, the API will not send the message! Please set different unique MessageId's in MessageIdList when using this API.

SendId is used to group the messages under one ID like campaign ID or group ID so they can be reported together.

If SaveParams is set to "yes", all parameters per recipient are kept in the database.

If SaveContent is set to "yes", all content (after customization with parameters) per recipient are kept in the database.