Assign message policy setting payload and merging details

[gazal_shaikh]

Can we map multiple object in assign message policy like below. can we use for loop to loop diffenet value to same entries and merge all objects?
{
"acc": [
{"main" : {
"key" : "obj1",
"value" : "obj2"
}},
{"main" : {
"key" : "obj3",
"value" : "obj4"
}},
{"main" : {
"key" : "obj5",
"value" : "obj6"
}}
]
}