question: nested array of objects

[barisro]

I am not sure if it is even possible but so far I failed to have one select2 field where I can select multiple cities for the schema below. Any help will be appreciated.

"Regions":{
    type:Object,
},
"Regions.Cities":{
    type:Array,
},
"Regions.Cities.$":{
    type:Object,
},
"Regions.Cities.$._id":{
    type:String,
},
"Regions.Cities.$.name":{
    type:Object,
},