Paste values from excel to selectinput

This is a sample application where in the table is displayed as per values selected from dropdown(more than 2 values). Right now the user can select only from dropdown. But can we add additional feature where (say from excel there are values column wise

Now the user can copy this values and paste it on selectinput. Then these values should be taken in the selectinput. Basically the user should be able to copy and paste values into selectinput widget

library(shiny)
library(DT)

dat <- mtcars

server <- function(input, output, session) {
  output$ui_view_vars <- renderUI({
    vars <- colnames(dat)
    
    ## using selectizeInput with drag_drop and DT
    selectizeInput("view_vars", "Select variables to show:", choices  = vars,
                   selected = "", multiple = TRUE,
                   options = list(plugins = list('drag_drop')))
  })
  
  output$dataviewer <- DT::renderDataTable({
    if (is.null(input$view_vars)) return()
    DT::datatable(dat[,input$view_vars])
  })
}

ui <- fluidPage(
  sidebarLayout(
    sidebarPanel(
      uiOutput("ui_view_vars")
    ),
    mainPanel(
      tabPanel("View", DT::dataTableOutput("dataviewer"))
    )
  )
)

shinyApp(ui = ui, server = server)