In a Swap event, the player is shown a series of possible trades that they can make.
You can set a limit to the number of trades that the player can make, and you can randomise the list.
"swap":{
"heroUpgrade":{
"showLimit": 3,
"swapLimit": 3,
"trades": [
{"Elemental HERO Avian" : "Elemental HERO Stratos" },
{"Elemental HERO Bubbleman" : "Elemental HERO Ocean" },
{"Elemental HERO Burstinatrix": "Elemental HERO Heat" },
{"Elemental HERO Burstinatrix": "Elemental HERO Lady Heat"}
]
}
},