Gradle - How to create a task at root level that calls 2 subprojects' task in build script

Question

How do I create a task (abc) at root level, such that running it, will run subproject A's bootRun task, followed by subproject B's bootRun task. Note that subproject A's bootRun task will run only after subproject B's bootRun task has runned.

I could only write task abc depends on subprojectA's bootRun task, but not sure how to indicate subproject A is dependent on subproject B. Try several syntax still fails

task abc{

   dependsOn ':subprojectA:bootRun'
}