Hi guys, thanks to both of you to reply my question and sorry also for my delay to reply you.
I´ve been comparing the list from Elements --> Room.Boundaries with the list from FamilyInstance.GetHost with every possible ways… but I received always an error an it was because of my Revit/Dynamo Version.
I just needed something like in the Dynamo Version from Revit 2019… something like List.ContainsItem… I didn´t know that It doesn´t exist anymore in Dynamo for Revit 2020 (my actual Version)
I have tried to cross the product with List.Contains with Equals… and everything… with the same result… still not working…
But at the end of my desperation I found a way… and I hope it will be helpful for you guys in future… thanks a lot to pay attention to my post.