Jenkins - prevent a pipeline/job from being triggered by multiple upstream projects -restrict one build to one upstream project

I searched a lot online but did not find an answer to this.

We have two projects A and B, which trigger a common project C as it's pipeline step. Now if A has triggered C (common project), and B also triggers C at around the same time, only one build of C is run and the result is consumed by both A and B. The build status in C shows "Started by upstream project A" and "Started by upstream project B" both.

How do I make project C first complete the build triggered by A and then start a new build for the trigger by B?

I solved my issue by using the lockable resource plugin in Jenkins. So my Jenkinsfile for projects A and B look like this

pipeline {
agent { ... }

stages {
    stage('Invoke project C') {
        steps {
            lock('project-c-lock') {
                script {
                    ...
                    ...
                }
            }      
        }
    }

}

Thus this step is executed only once and synchronization takes place. It's important to have the same lock resource name.