Bulk Email Relay Server Setup in php

we need you to setup a relay email server in a linux platform you need to program a php script which runs in a linux/unix server our customers have various bulk email sender softwares in which they input 5 parameters in their smtp settings window of the software 1. server name 2. user name (email address) 3. password 4. port number 5. SSL (ON OR OFF) for eg. if they enter gmail smtp settings in their bulk email software, the mails will be gone through the gmail smtp. now, instead of gmail smtp settings, they will specify the server name and other parameters of our dedicated linux server in their bulk email software so that mails will be recieved by our linux server and that emails will be relayed to gmail smtp. this is the script you have to develop. customer will specify only one smtp server name and username and password. but in our linux server, there will be 10 or more gmail smtp accounts for a particular username and password which the customer specifies in their bulk email software. then, the emails come to our linux server and will be relayed to 10 different gmail accounts one by one automatically. it will automatically shift to next gmail account after 250 emails are sent and it goes on until all 10 gmail accounts are used up. ie. our customer will see only our linux server settings in their bulk email software. but emails will be gone through gmail smtp after coming to our linux server. after sending 250 emails from a gmail account, that gmail account should be marked as sent in our linux server. if the customer breaks in between the sending, then when he resend, the unmarked gmail account should be the one through which messages should be continued. administrator should be able to create any number of users and configure atleast 10 gmail accounts under each user. when 100 users are using the linux server, the relay should take place simultaneously. Payment - Once the demo of this is setup in our linux server in such a way that basic functionality of relay is working fine, we will make 50% of the payment. after that when the functionality of creating different users and other things are complete we will make another 50% payment thanks