Make use of the /pa invite and /pa challenge commands built into the parkour plugin. Last I recall, features like these were part of the reason we got this plugin, yet we've never been allowed to use them. The latter would actually be really cool.
What's even more mind-boggling is that the actually useful parts of the plugin were removed. We can't run /pa list or /pa info in most places now, which is absurd. I want to be able to know what map my friend is doing without having to distract them to answer me. At this point I kinda wonder why we ever even got this plugin at all...