Is there a probability option in XP like in RM1?

Start with page 1, control variables.
Choose a variable, perhaps one dedicated to random numbers.
Choose the random bullet, having it choose from 1 to however many possibilities there are (if there are 4 possibilities, then set the second number to 4).
Hit okay.
Next line of code, page 1, conditional branch.
Page 1, the variable bullet.
Choose the variable.
Equal to 1, OK.
Then put in what you want to happen in the first choice.
Then make a conditional branch for every remaining variable, with their effects occurring.

Why do you keep making new topics? Stick to one topic for these XP questions.

And didn't Draygone already tell you about this kind of thing? You do it again, you'll get a warning.

Which reminds me, is it possible to merge topics?

You know, I've never had to do that.

I don't think a merge is available right now.