How to substitute repeated script statements in multiple functions by a predefined script block or other mean?

I have multiple functions. By the end of the function they all need to go through exactly the same couple of lines of code, doing some logistic work. How can I define these couple of lines of code into a script block outside these functions and be able to use for all functions, either global reference or passed in as an argument(less preferred)? These lines of code will involve both global and local variables. The ideal is whenever I need to update the logistic work content, I can update it in one place, like script block definition, instead of using a function, which seems overkill for a few lines of codes. Thanks.

function A {
    ...
    $var1 = $global:x + 1
    Write-Host var1 value is $var1
}

function B {
    ...
    $var1 = $global:x + 1
    Write-Host var1 value is $var1
}

$global:x = 0

A

B