How does the schedule pipeline work with variables?

Hello everybody,

I am currently using several schedule tasks for the pipelines, which use the same code in the background. Now I would like to add variables to the schedule tasks and then transfer the variables to gitlab_ci.yml. In gitlab_ci.yml I would like to continue to use only one configuration for all schedule pipelines. I would like to use the variable from gitlab_cy.yml in the test and only run the test data with the variable name “test1”.
In short, I have pipeline A, B, C with the variables testA, testB, testC in the Schedule Piplines. The variables are also stored in gitlab_ci.yml and my test should e.g. only carry out the test for the test data “testA”.

Is it possible in gitlab? How can I do it? Unfortunately I have not found a solution or anything similar in the documentation.