Hello,
You can't change sender and receiver at this moment. You can set up several receivers, but can't change.
You can change message by using sendemail (Input1, Input2) script command by changing Input2.
Soon, we'll release new version of TeslaSCADA2. In the new version we'll integrate possibility to work with services like IFTTT (ifttt.com).
These services we'll let you implement this possibility I think for some E-mail.
About digital conditions. You can use script like this one:
if (Tags.A==1 || Tags.B==1 || Tags.C==1){
Tags.output = 1;
}
Best regards,
Ruslan