I need to select a character and if it's selected (I have 3) I want the others to disappear. I'm trying to handle this for hours, tried to define a variable and if, for example, character 1 is selected, variable becomes 1, and I have if conditions like if d=1 then show etc… any ideas?

Sprite 1

when this sprite clicked
broadcast [selected 1 v]

other sprites

when I receive [selected 1 v]
hide

sprite 2

when this sprite clicked
broadcast [selected 2 v]

other sprites

when I receive [selected 2 v]
hide

etc.
Just make sure that when it receives its own broadcast it doesn't hide.

Thanks so much! Worked. I have another question, my objects move when I click them if accidentaly moved mouse slightly, I want them to stay still. How can I do it?

Use it in full screen or view the project page. That can only happen in the editor.