search filtering not working w/ complex data on different columns

I have an issue with filtering complex data,

The data I got as the following:
```
"customers": [
{
"name": "customer name",
"email": "cname@email.com",
"address": [
{
"country": "cCountry1",
"city": "cCity1"
}
]
}
]
```

```

ID
Name
Email
Phone
Country
City
Status

```

```
showCountry(cell) {
if (cell.length > 0) {
return cell[0].country
}
return null
}

filterCountry(cell) {
if ( cell.length > 0 ) {
return cell[0].country
}
return null
}
```

I tried also `filterFormatted`, the issue that both are only working with the last call, which is in this case `address.city`. I don't know why they are filtering only once, is there any explanation on how to fix this or another way to filter complex data?