Jenkins - trigger multi-branch pipeline on multiple upstream change - jenkins

Question

I'm kind of new to Jenkins, I'd like to setup Jenkins trigger for the following case, successful build of either projA or projB should trigger build of projC, I'm using declarative Jenkins syntax, and projA..C are multi-branch projects.
projA --> projC
projB --> projC
I follow the example of #2 from Jenkins: Trigger Multi-branch pipeline on upstream change and setup projC to be triggered on projA (or projB), but not sure the syntax for projC to be triggered either on projA or projB.
In addition, is it possible to pass values from projA and projB to projC as part of the triggering mechanism? What's the syntax if possible.
Any help is appreciated.
This is the code:
pipeline {
agent any
parameters {
string(name: 'MY_BRANCH_NAME', defaultValue: '${env.BRANCH_NAME}', description: 'pass branch value')
string(name: 'MY_VERSION', defaultValue: '1.23', description: 'My version')
}
stages {
stage('Build in dev') {
steps {
echo 'Building dev..'
}
}
}
}

Answer 1

I think you need to look at this from the other way around. Don't think of C looking for A or B to complete. Think of A or B triggering C if they succeed.
In your A and B projects, if you consider the build to be successful by whatever your criteria is, use the build step to trigger C.
If you want to pass simple values to C, make C a parameterized build and pass the parameters in the build step.
post{
success{
build job: 'C', parameters: [booleanParam(name: 'bool1', value: true), string(name: 'foo', value: 'bar')], quietPeriod: 10
}
}