Problem with loop and count in a textfile

Question

Hi everibody,
i need some help,
i've got this text file
---------------------------- start ------------------------------

GENUARDI ADOLFO
90100
04800530828
VIA ORETO 139
MARCHESE SALVATORE
90100
00464940824
PIAZZA CARMINE 40
LA MENDOLA LILIANA
90018
04109670820
VIA BAGNI 1
BOVA AGOSTINO
90018
04572110825
CORSO UMBERTO E MARGHERITA 37
RESTIVO ANTONINO
90018
04357320821
VIA PANDOLFINI F.D. N.24
CORRERA MARIA TERESA
90040
03620280820
VIA PROVINCIALE 76
etc,etc,etc

Well i'm tryng to read the file and count 4 line and take the text ,count another 4 line and take the text,count another 4 line and take the text,so till the end of the text.
How can i Do?
Thanks