I suppose your approach would be to load the entire Excel file to UiPath using Read Range activity.
You need to provide it a Data Table variable as the output (there is plenty of relevant information on the forum to achieve that).
Then, your next step would be to do some actions on the input DataTable to extract your values OR to do actions based on those values.
The easiest way to go through your records in a DataTable is to use a For Each Row activity (also, plenty of relevant information on the forum).
Here, depending on your end goal, the approach might vary. For example, you can add and IF condition within your For Each Row activity to detect if the row contains an empty string. This would mean you can do a set of actions on the bunch of rows and as soon as the empty strings shows up, you can continue with the next bunch.
I hope that helps a bit