In the main pipeline I want to work with the secondary pipeline and other functions decorated with 

PipelineDecorator

. Does ClearMl allow this? I have not been able to get it to work.

Usually when we think about pipelines or pipelines, the nested pipeline is just another Task you are running in the DAG (where the target queue is the services queue).
When you say nested pipelines with decorators, what exactly do you have in mind ?