Hey Isadora, could you explain a bit more what you are trying to do?
If I read your blueprint now it does not make much sense 
What you are doing now is:
for every trace (from your multispheretrace) you get all TARgets in your level
set their radar to true.
If you want to put all targets - radar to false except the hit ones you should first get all TARgets and set radar to false, then multi trace and cast the ‘Actor’(from hitresult) to TARget. If this succeeds set the Radar to true of this actor.