Parallel stages from list in Jenkins

Question

I have something like:

pipeline {
agent any
stages {
    stage('Run Tests') {
        parallel {
            stage ('stage1') {
                steps {
                    catchError() { 
                        build job: 'test1'}
                    catchError() { 
                        build job: 'test2'}
                }
            }
            stage ('stage2') {
                steps {
                    catchError() { 
                        build job: 'test3'}     
                    catchError() { 
                        build job: 'test4'}         
                }
            }
            stage ('stage3') {
                steps {
                    catchError() { 
                        build job: 'test5'}     
                    catchError() { 
                        build job: 'test6'}         
                }
            }
        }
    }
}

and it works fine, but I would like to modify it to optimize the duration of pipeline. So sometimes it would be to run:

• test1 on stage1
• test2 on stage2
• and test3, test4, test5, test6 on stage 3

sometimes it would be to run:

• test1, test2, test3 on stage 1
• test4 on stage2
• test5, test6 on stage3 etc

Is it possible to define number of stages and list of tests? In this example I would like to have 3 stages and list of 6 tests and it should works like:

• first three tests are started parallel, each on different stage
• after first test is finished, next test from the list is started on the same stage as finished test