Okay. Here's how you do it. It's going to be really troublesome for you to do it, but you can if you want.
There's two methods for doing this. The first method doesn't require any scripting with the password part, but the second method does. I'll just show you the first method for now. If you still want to know how to use the second method, just let me know.
Okay. This is how you do it. Say, for example, at the end of the first story game you have your main character choose whether they want to kill another character or let them live. Make a variable called %KILL, or whatever you want to name it. If the main character kills the other character, leave the variable %KILL alone. If they let the other character live, set the variable %KILL to 1. I expect you know how to do that. If the variable %KILL is 0, lead them to a page with the password "1234", or whatever you want. And if the variable %KILL is 1, lead them to another page with the password "5678", or whatever you want.
Then on the second story game, before asking them for the password, make four blank pages. Make four links on the first page. Set three of the links to link back to the first page, and the fourth link to the second page. Label those links with the required numbers. Then on the second page, make another four links. Set three of those links to link back to the second page, and the fourth link to the third page. Same thing for the third page, and for the fourth page.
After that, well, basically if they got the password right, you'd know if they killed the other character in the previous story game, and then you can proceed from there.