Jenkins Pipeline - Call functions in shared jar

Question

So here is my project setup

1. A separate groovy project
2. Multiple pipelines

All the pipeline scripts refer to the shared groovy project. I went through the shared libraries and all of the needs to be registered in Jenkins global configuration.

Is there any way to do without it? I tried using Grab but ended up with the error

java.lang.RuntimeException: No suitable ClassLoader found for grab