How can I skip Tasks with variables as filter criteria

I have use case where there are some serviceTasks. Each service task contains some variables like inputParam, outputParam. Now I want to skip serviceTasks for some set of inputParams. For that, I want to store the inputParam as list globally for process and check for serviceTask whether inputParam is in the list or not.

Sample BPMN is like this:

<?xml version="1.0" encoding="UTF-8"?>

      //some logic to store set of inputParams which can be accessed by all service tasks. Not sure about this logic
      <flowable:field name="inputFilterList">
               <flowable:string>{"inputParam1"}</flowable:string>
      </flowable:field>

      <serviceTask id="INPUT_REFRESH_PARAM1" name="Task execute 1" skipExpression="${//expression to check if testInputParam1 is in inputFilterList//}" flowable:async="true" flowable:triggerable="true" flowable:class="RefreshTaskDelegate">
         <extensionElements>
            <flowable:field name="inputParam">
               <flowable:string>["testInputParam1"]</flowable:string>
            </flowable:field>
            <flowable:field name="outputParam">
               <flowable:string>["testOutputParam1"]</flowable:string>
            </flowable:field>
         </extensionElements>
      </serviceTask>
      <serviceTask id="INPUT_REFRESH_PARAM2" name="Task execute 2" flowable:async="true" flowable:triggerable="true" flowable:class="RefreshTaskDelegate">
         <extensionElements>
            <flowable:field name="inputParam">
               <flowable:string>["testInputParam2"]</flowable:string>
            </flowable:field>
            <flowable:field name="outputParam">
               <flowable:string>["testOutputParam2"]</flowable:string>
            </flowable:field>
         </extensionElements>
      </serviceTask>

How can I achieve this functionality?

Hallo @JimMoriarty
you want to check for conditions and decicde if your task should executed or not?
You can check out this link
Conditional sequence flow and this Gateways

Greetings

Christopher

Thanks @WelschChristopher.
Can you also tell me how I can set my own variables at process level, so that those can be accessed across all tasks?

If you use execution.setVariable(name, value), the variables will be process instance scoped by defaul.

Thanks @joram
I set _FLOWABLE_SKIP_EXPRESSION_ENABLED to true like this.
variableMap.put("_FLOWABLE_SKIP_EXPRESSION_ENABLED", true) startProcessInstanceById(processDefinitionId, businessKey, variableMap)
In my BPMN file I have flowable:skipExpression="${1==1}" (kept this for testing purpose). Even now, the task is being executed instead of skipping. Did I miss something?

PS: I verified whether it is set before starting the execution or not. It is set.