Custom specific conditions to interact
Besides the server validation if a player is allowed to interact you can add your own conditions in AC_PC_Interaction -> ServerSpecialConditionsNeededToInteract. In this function you can find an example for a locked door that only can be accessed if the player has picked up a key card before. Please note that this is an example in the demo map and it relies here on the player controller that comes with the interaction system BP_InteractionSystemPC. In there it stores in a boolean variable if the player has picked up a key card. If you want to implement your own condition and you have a different player controller, it is no problem. You can cast in ServerSpecialConditionsNeededToInteract to your own player controller and access information (if necessary) about picked up items and more - Interaction Notify events for player (Event Dispatchers and Interface) could be useful for this.