Can sendmail act as outbound load balancer to mult-rcv mail srvrs

[RandyS56]

We have been given 4 different email addresses to contact our "message relay provider". (This Satelite Co. relay's messages to our units).

I would rather the application (developers) that sends the email, NOT have to keep track of the "Round Robining" to each of these 4 mail servers.

Current Architecture -> this is done with "PEN", and Direct circuits. "PEN" simply says "I'll take this request to an IP and send it to 1 of 4 IP's port 25. the application transacts directly with the (sendmail) smtp interface. The problem is "PEN" has NO Buffering capability like sendmail as a client does.

I would rather queue / (hold until successful) the application requests using sendmail.

Does anyone know if "PEN" (or something like "pen") can work on TOP!! of sendmail? Or is there a direct way sendmail can Round Robin out based on a Single TO: address request?

Or some other way? And I am trying to avoid an appliance like "F5 networks BIG-IP Load Balancer. I really would like to provide this to my application programmers via software. We run Linux 2.6 (RH).

Thank You Very Much for your comments.