my %HoA;
print "Input Data parsed into 3 columns:";

while (my $line = <DATA>) {
	my ($col1,$restcol) = split /:\s*/, $line ,2;
	my @restColumns = split '', $restcol;
	$HoA{$col1} = [@restColumns];
}

print "Dumping Output \n";
for my $dataKey (keys %HoA) {
    print "$dataKey: ", join("\t\t", @{$HoA{$dataKey}}), \n";
}

__DATA__
ULTRIX              :       CW18.72.0.3          IP-HOST1.log
DEC_DECSTATION      :       CW180.72.0.3         IP_HOST_AL.log
DEC_DECSTATION_ADDR :       CW180.72.0.3         IP_HOST_al2.log
FOR_VISITORS23_HOST :       HL617.253.1101.2     IP_HOST_hostinfo.log
FOR_VISITORS24_HOST :       HL617.253.1101.2     IP_HOST_hostinfo2.log
FOR_VISITORS25_HOST :       HL617.253.1101.2     IP_HOST_webform3.log
FOR_VISITORS25_HOST :       HL617.253.1101.2     IP_HOST_webform4.log
FOR_VISITORS25_HOST :       HL617.253.1201.2     IP_HOST_webform4.log

##</code><code>##

FOR_VISITORS25_HOST       HL617.253.1201.2     IP_HOST_webform4.log
DEC_DECSTATION            CW180.72.0.3         IP_HOST_AL.log
FOR_VISITORS23_HOST       HL617.253.1101.2     IP_HOST_hostinfo.log
DEC_DECSTATION_ADDR       CW180.72.0.3         IP_HOST_al2.log
ULTRIX                    CW18.72.0.3          IP-HOST1.log
FOR_VISITORS24_HOST       HL617.253.1101.2     IP_HOST_hostinfo2.log

##</code><code>##

FOR_VISITORS25_HOST       HL617.253.1101.2     IP_HOST_webform3.log
FOR_VISITORS25_HOST       HL617.253.1101.2     IP_HOST_webform4.log

##</code><code>##

FOR_VISITORS25_HOST       HL617.253.1101.2 :     IP_HOST_webform3.log
FOR_VISITORS25_HOST       HL617.253.1101.2 :     IP_HOST_webform4.log

##</code><code>##

FOR_VISITORS25_HOST       HL617.253.1101.2     IP_HOST_webform3.log 
                                               IP_HOST_webform4.log
                                               ......
                                               ...... <more values for same key>