I'm not sure if this will address what you're hoping for but the way i would approach it would be to have an object (that isn't going to be deleted, maybe on the player object itself) that works as a sort of "monitor" and have it using the mouse-pick every frame and transferring what it's over to a game-object variable. you might need to filter it so that it won't pick on colliders or other objects you might have in the scene that might interfere. Then, right under it, have a "set fsm gameobject" action every frame telling another fsm to update the game object variable in a new FSM (this can be on the same object in the scene and might make it easier to set up too.)
in this second FSM, have a sort of testing system that controls the overlay or other indicator you want to use (such as a projector that's over the object you want or a gui element that's at the mouse point or something like that.) to make it less intensive, you can have it only trigger whenever the game object variable has changed (the way it seems to work is that the mouse pick won't be removing or changing the game object variable every time it updates... so, a "game object changed" action should work with this kind of setup.)
So, in this one, let's say you're using a projector... and you have your objects set up with the proper layers (not tags... i made this mistake myself a couple times before i figured it out.) you can have this projector be the thing that has the monitor on it and the mouse pick action is set to ONLY look for what you've set in the layers as "objects to click" or "enemies" or "units" (etc.)
When you hold the mouse pointer over the object, if it's detecting this and you have the projector's position be set to the same position as the object you're hovering over, that should give you an indicator that will go to that position. if the object is moving, however, you might need to have the system adjusted a bit so that the "Set position" is always updating with the positional data of the object you want it to hover over.
I'll see about cobbling something up like this (since i want to add one to my own game as well that does something like this also... so, no time like the present, eh?) if you need some additional help (and it'll give me a chance to test out this idea since as things are, i'm only going on what i would expect it to do and haven't tested it myself yet... but don't let my lack of testing it stop you from trying, almost everything i learned i learned by trying things out and experimenting and you might come up with a different and/or more lean approach to do it on your own.