using group_by with filtered inputs in shiny for map

I have what may be a complicated question. I'm trying to build a filterable map with shiny. I'm using the selectizeGroupUI feature because it allows you to easily filter inputs in a way that links all the columns together.

There are six geographic based columns, and the hierarchy from largest to smallest goes as such:

district - subdistrict - territory - region - turf - areas

The way I setup the filters does part of the job, but I want it to group_by in accordance to the selected inputs as well, but with a downward hierarchy

For example: If I'm filtering by region, I want it to group_by the turf tied to that region. If I'm filtering by district, it will group_by subdistrict, and so on.

Make sense? Here is my script (and here is the link to the shapefile):

library(sf)
library(shiny)
library(shinyWidgets)
library(dplyr)
library(leaflet)
library(mapview)

 df <- 

 ui <- fluidPage(
   fluidRow(
     column(
       width = 10, offset = 1,
       tags$h3("Select Geography"),
       panel(
         selectizeGroupUI(
           id = "filters",
           params = list(
             District = list(inputId = "district", title = "District:"),
             Subdistrict = list(inputId = "subdistrict", title = "Subdistrict:"),
             Territory = list(inputId = "territory", title = "Territory:"),
             Region = list(inputId = "region", title = "Region:"),
             Turf = list(inputId = "turf", title = "Turf:"),
             Areas = list(inputId = "areas", title = "Designated Areas:")
           ))
         #), status = "primary"
       ),
       leafletOutput("test")
     )
   )
 )

 server <- function(input, output, session) {

   res_mod <- callModule(
     module = selectizeGroupServer,
     id = "filters",
     data = df,
     vars = c("district", "subdistrict", "territory","region", "turf", "areas")
   )

   output$test <- renderLeaflet({

     x <- res_mod() %>% st_sf()

     res <- x %>% filter(is.null(input$region) | region %in% input$region,
                         is.null(input$turf) | turf %in% input$turf,
                         is.null(input$areas) | areas %in% input$areas,
                         is.null(input$district) | district %in% input$district,
                         is.null(input$subdistrict) | subdistrict %in% input$district,
                         is.null(input$territory) | territory %in% input$territory) %>% mutate(sales = tidyr::replace_na(sales, 0)) %>% 
       group_by() %>% summarise(totals = sum(sales))

     mapview(res, zcol = "totals")@map

   })

 }

 shinyApp(ui, server)