The best way to ensure that anyone with general scripting experience that sees this topic will try to help you is by providing all the necessary components. We don't like to run around a whole lot. If for example you knew Ruby and you walked into a RGSS help topic and saw that a person was asking for help on five different scripts and they didn't provide any links, and pictures, any demo, or any scripts. Would you help them?
So what do you mean by portal engine? Could you provide a link to a demo or the actual script Nears I mean? I remember Arev's script having a lock event or lock screen particle effect. So I guess in your case you could create a temporary event give it a particle effect and manipulate it to your heart's content.