I might not be the right person to say much for help request. But, after reading what you said.
First. How would any of your friends know you are getting a room? Would it not be your own mistake to tell that something like that is coming to your way?
There is no known way to prevent losing underground items if you openly tell that you got them. You know as well everyone else that the moment you get something what others can't get right on spot. It is going to be reported, that is the nature of mankind.
Second. What kind of help you are asking here? Should we wipe your friend list clean?, delete all of them and maybe few more just to be sure?
Third. Personal matters, relationship matters and a like. Are generally something others can't help out much with(meaning imvumafias). Try talking to who ever it is been so jealous of what you got. Block, remove them from your circle of people. I do not see a justified reason in that for a organisation to attack. That would be very foolish and soon it would bloat out that everyone would come to ask for the most minor reasons for collective help.
Fourth. To prevent yourself from losing item/s. Be smart how you are going around getting them. There are several ways of adding few extra steps to ensure more safe way. Like, use second account for the item. Open up a room and just use the url to get in and out. There is no need to go yell or even tell anyone around you that you have something new. If you are doing so for the bragging rights, then you are only shooting at your leg.