Facilitate if/else condition in conjuction with parameters

[Przemk00]

The current state: I have a working workflow with 3 tasks with several parameters.

The change: I want to modify the workflow to add 4 tasks - if/else so that based on one of the parameters (call it xyz) the workflow will not proceed after 1st task.

The problem: I cannot do so as it has to be job parameters in the current state whereas the xyz is 'just' a parameter. How to overcome the issue?

[Przemk00]

The logic should be simple if the xyz parameter equals 1000 then run the other 2 tasks otherwise, do not run the rest.