R Shiny - Is it possible to nest reactive functions?

In R-Shiny. Trying to break up a really long reactive function (thousands of lines!). Hypothetically, is it possible to nest conditional reactive functions, something similar to:

STATE_filter <- reactive({
 
   if(input$selectcounty ends with "-AL") {
    run AL_filter()
  }
  else if (input$selectstate ends with "-AR"){
    run AR_filter()
  }
  else {
    return("ERROR")
  }
})

Thank you!