How to force a macro to wait for a large sheet sort to finish

This may be a simple problem but I have looked and cannot seem to find any answer to this. Basically, I have a large sheet. In my macro, I fill-handle a formula down Col I which holds either a "" or "-" (formula result). I then want to sort the data by this Col I (put all rows with a "-" in Col I at the bottom), and then copy those rows with the "-" and paste them in another sheet. The problem is that the sort is not finishing before the macro hits my copy code. How do I force the macro to wait for the sheet to finish sorting before moving on. For that matter, how am I sure the fill-handle is finishing (this could also be a quite large task) before the sort is happening. The only similar thing was a backgroundrefresh = false on querytables, but this is not a query table. Help?

I should say as well that I would rather not break up the macro code into separate macros which run in sequence.