Sorting data in groups

I have multiple projects and each project has data on 3 consecutive rows. Between each project's set of 3 rows is a blank row sepearation them. The projects are in no specific order and need to be placed in order. In one column I have a project number (on all 3 rows for each project) that can be used to sort.

How can I sort these and keep a blank row between each set of 3 rows for a particular project?

I have thought about doing it as follows but hope there is a better way:
have a macro perform a sort on the project number for the entire data set then have the macro go through and add a blank row at each change in project number.

If this is the best way to handle this, I will need some generic help on the verbage of the code to pull off the insertion of blank rows at each change in project number.

Thanks.