In a overview I have:

In column A projectnumbers. Projectnumbers are sorted, but projects
can exist more then 1 time. So, a project can have reveral rows. In
the columns B-G there is information about the projects.

For example: in A1-5 there are projectnumbers, all the same.In B1-G5
information about all these projectparts. Row 6 is empty. In A7-A10
thera are also projectnumbers, in B7-G10 information. Row 11 is empty
again, and so on.

What I want is a option to sort these blocks. The order of the rows in
the project must remain.

Is this possible? Any help would be appriciated.