Sending data between PHP files and then to client

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PHP

Hi
I have one PHP file, php1 sending data to another, php2.
I have a website with an EventStream set to php2.

Ideally, php1 would send the data to php2 and it would then echo it into the stream. However, I don't believe it works like that as there are two separate instances of php2 due to the different connections from php1 and the website.

Is there a better alternative to the following?:

php1 -> php2 -> file
file -> php2 -> website

php1 sends to php2, which writes to a file.
the website requests from php2, which reads from the file and echos

What I have tried:

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