How to send JSON response using 2 collections in a mongdb

I have two collections in my mongodb. One collection contains id and location while the other collection contains id and various other information. I am trying to create a route such that we we use app.get for http://localhost:3000/:location , it should find the ids for the searched location and then use those ids to give a json response from the detailed collection.

In the code, I am using just one collection and giving a response from it.But, want to use the id provided in the response to create JSON response from the otherdatabase name Specialty.

app.get('/hospital/:location', (req, res) => {
    const city = req.params.location
    console.log(city)
    Hospital.find({city:city},(err, Hospitals)=>{
        if(err){
            res.send('error')
            next();
        }
        console.log('Search ho gya hai')
        res.json(Hospitals)
    })
});

Schema 1

const hospitalschema = new Schema({
    placeid: String,
    name: String,
    city: String,
    address: String,
    latitude: String,
    longitude: String,
    phone: {
        type:String,
        default: 'Phone number not available'
    },
    rating:{
        type:String,
        default: 'Not Rated Yet'
    }
});

Schema 2

const hospitalspecialityschema = new Schema({
    placeid: String,
    specialities:{
        type:Array,
        default:''
    }
});

I am trying to the the hospitals with particular speciality and then using the placeids I want to show the collection of Schema 1 as JSON output.