With the Lockable Resource plugin, you can define say resources "mydev1", "mydev2", "mydev3", give them all a "mydev" label, then configure your job to have "label:mydev" and "Number of resources to request:2". That works nicely. But, I would like to use this from a section of a pipeline, where after a slow build, I invoke a parallel block where I use one "mydev" in each leg, so that I can restrict timespan of the critical section to just the portion it needs to be.

But, per the documentation on https://wiki.jenkins-ci.org/display/JENKINS/Lockable+Resources+Plugin and the code on https://github.com/jenkinsci/lockable-resources-plugin/blob/master/src/main/java/org/jenkins/plugins/lockableresources/LockStep.java#L23, the lock step in a pipeline you have to provide a 'resource', and there is no mechanism to provide a label.

Can label support please be added?