I have a php program (alpha.php) which receives $_POST from an HTML source.
The alpha.php program examines the data in the $_POST and determines which other PHP program (beta.php, gamma.php, delta.php) is to receive the data as $_POST. In other words alpha.php is to act as an forwarding agent. There is no response required.
I cannot see how to have alpha.php send the data as a $_POST to the other php program and how to activate the other php programs to receive the data.