How to bind two xts data environments in R

I am completely new to R and I am learning how to program in R to get historical stock index data. I am planning to build an daily update code to update historic index data. I use a data environment call "indexData" to store the data as a xts. But unfortunately, the rbind or merge does not support data environments. They only support objects. I am wondering whether there are any workarounds or packages that I can used to solve this. My code is the following:

  indexData<-new.env()
  startDate<-"2013-11-02"
  getSymbols(Symbols=indexList,src='yahoo',from=startDate,to="2013-11-12",env=indexData)
  startDate<-(end(indexData$FTSE)+1)
  NewIndexData<-new.env()
  getSymbols(Symbols=indexList,src='yahoo',from=startDate,env=NewIndexData)
  rbind(indexData,NewIndexData) #it does not work for data environments

Much appreciate for any suggestions!