Now, I understand website hosts can be expensive and along with servers costs you can't really have 3 websites, but to keep things more organized I was thinking of having sort of a website portal for the 3 skyblock servers. This would allow players(when they log in/go to the website) to view a page where there are 3 options, skyblock.net, skyblock.org, or hellblock.net. Each option would redirect you to the appropriate home page, where you would view server news, rules, updates, etc., and then there would be a forum like we have currently, for each of the options, where your account would work on all the sub-forums, but you would have different ratings, followers, etc., and there would be different threads for reports, off-topic, forum games, applications, suggestions, for each of the sub-forums, that way Staff Members and Users could navigate the forum easily, and reports, and all important matters would be handled for each server efficiently, it may take some time to work it all out, but I think it's a good idea.
I feel like by having everything on one website, it brings the community together. For example, I don't play much .org, but because it's all together, I can connect with players who primarily play there. I understand what you're getting at and it's not a bad idea, but I feel like it would divide the community.
This would probably be limited by the forum software, plus it creates a form of separation when the forums is meant to be for all servers to come together. Unless we just have like a sub forum for server specific discussion or something that would not segregate the community than that would be quite good.
The whole point of a forum is to have it unified and together, essentially all in one place. That would split up the community more and make contacting your friends harder to do. Assuming you don't mean a landing page and have the forums how they are now, but that's not worth to implement without a dedicated forum Admin.