How to implement support for my language using a plugin?

I wrote my interpreted language in Java, but here's the problem, I can't make a plugin to support my language. My language is very similar to Java and C# (Object-oriented, strongly typed). I have a Lexer, I have a Parser (I even made a PsiListener for the AST generator). But Intellij IDEA has its own lexer and parser system. How can I combine them?

I couldn't combine my PsiListener with Intellij's PSI system because my parser and lexer require the entire code at once, but Intellij doesn't provide it.

So how can I combine the lexer and parser of my language with the plugin for Intellij?

https://github.com/ReStudios-Dev/ReLang