Да. Это можно сделать с помощью отправленной триггера.
private void SendEmail(string triggeredName, Subscriber subscriber) {
CreateResult[] results;
string requestId;
string status;
var t = new TriggeredSendDefinition { CustomerKey = triggeredName };
t.RefreshContent = true;
t.RefreshContentSpecified = true;
var s = new TriggeredSend { TriggeredSendDefinition = t, Subscribers = new[] { subscriber } };
CreateResult[] r = _client.Create(new CreateOptions(), new APIObject[] { s }, out requestId, out status);
var r2 = (TriggeredSendCreateResult)r[0];
//add your own try/catch, etc
}