Doing something like that in a optimal and working way is too soon with the current tools. Because:
-There is no "when allies use skills" trigger yet. So you'd have to set up a common event and tie it to EVERY or your actors with the trigger "entity_action_end".
-You'd need to check the feasibility of that passive. How far the allies are allowed to be ? What if there is no room for the user to land ? Is the actor with the passive alive ? Is he able to move ? And not bound by any state ? Ect.
-For now there is no way to designated THAT target under the cursor using plugin commands. So, the person with the passive won't really be able to follow up on the same target.
-There is no "clean" way for now to know which skill/type of skill is being used.
You can't come up with someting 100% optimal and bug free now but your common event can look like this:
Assuming your party is composed of Duran (the person with the passive), Angela and Lucius.
Angela and Lucius should have this event tied to them.
<letbs>
tied_events: 10
</letbs>
What will happen is, every time they end an action, Duran (Actor(1)) will jump near THEM, and use the skill(15) to the closest target.
The condition is there to make sure Duran managed to correctly jump where he should.
What I would suggest you is, instead of making the actor jump, switch his cells with the ally. This is safer.
Your advanced common event will look like this, then:
And here's the result:
But there are still some problems.
-The common event is broken if the ally isn't in range with the target. We'd have to check that condition at the beginning of the common event, but there is no proper tool for this yet.
-The ally's target is still not identified. Actor(1) attacks the closest enemy to him.
As you can see it's too soon yet if we want to do complicated stuff like that. Be patient, by the 1.0 version we'll have plenty of tools and means to achieve the most craziest things.