I think it would be very useful and handy to be able to place a token on the field, and link that token to a handout. If a player then clicks this token, he or she should be shown the linked handout. This would allow you to add a token somewhere in a dungeon with maybe a piece of text, or an image, and only the player(s) who find the token in question would be able to view it. To expand on the idea, maybe you could set a range for the handout token. If a range was set, only player whom's token is within this range may click on the handout. Another alternative would be to limit clickability by line-of-sight (using the Dynamic Lighting)