Need a "leave online note" message system

[SouFooOoO]

Basically, I need help with an NPC being able to save messages left by players.

Example:
Player1 comes into the level, and say "leave message <message>", the npc save the message.
Player2 or any other player could come in and say "check message" and the npc would display the message left by Player1.

Example2:
Player1 touches NPC1, says "leave message <message>" and NPC1 saves it.
Player2 touches NPC2 and says "leave message <message>" and NPC2 saves it.
Player3 touches NPC1 and says "check message" and only NPC1 would display the message left by Player1.
Player3 touches NPC2 and says "check messages" and only NPC2 would display message left by Player2.

Thanks in advance!