you could do this
have your item call a common event, in that common event you do conditional branch:
conditional branch :[character 1] is ["state"] inflicted
change skills:[character 1] add "spell
else
conditional branch: [char 2] is ["state"] inflicted
change skill: [char 2] add "spell"
and so on and on for all characters
make the item add a blank status effect and it doesnt change your status from normal but adds the skill. like if you use status effect # whatever that you dont have a real status effect on
i just noticed that this is for VX, it works in XP but i dunno if itll work in VX but worth a shot