Consolidate several lines of a CSV file with firewall rules

[Starriol]

Hi guys.
I have a CSV file, which I created using an HTML export from a Check Point firewall policy.
Each rule is represented as several lines, in some cases. That occurs when a rule has several address sources, destinations or services.
I need the output to have each rule described in only one line.
It's easy to distinguish when each rule begins. In the first column, there's the rule ID, which is a number.

Let me show you an example:

NO.;NAME;SOURCE;DESTINATION;VPN  ;SERVICE;ACTION;TRACK;INSTALL ON;TIME;COMMENT
1;;fwxcluster;mcast_vrrp;;vrrp;accept;Log;fwxcluster;Any;"VRRP;;*Comment suppressed*
;;;;;igmp**;;;;;
2;;fwxcluster;fwxcluster;;FireWall;accept;Log;fwxcluster;Any;"Management FWg;*Comment suppressed*
;;fwmgmpe**;fwmgmpe**;;ssh**;;;;;
;;fwmgm**;fwmgm**;;;;;;;
3;NTP;G_NTP_Clients;cmm_ntpserver_pe01;;ntp;accept;None;fwxcluster;Any;*Comment suppressed*
;;;cmm_ntpserver_pe02**;;;;;;;
	
What I need ,explained in pseudo code, is this:

Read the first column of the next line. If there's a number:
	Evaluate the first column of the next line. If there's no number there, concatenate (separating with a comma) \
	the strings in the columns of this line with the last one and eliminate the text in the current one

The output should be something like this:

NO.;NAME;SOURCE;DESTINATION;VPN  ;SERVICE;ACTION;TRACK;INSTALL ON;TIME;COMMENT
1;;fwxcluster,fwmgmpe**,fwmgm**;mcast_vrrp,fwmgmpe**,fwmgm**;;vrrp,ssh**;accept;Log;fwxcluster;Any;*Comment suppressed*
;;;;;;;;;;
;;;;;;;;;;
3;NTP;G_NTP_Clients;cmm_ntpserver_pe01,cmm_ntpserver_pe02**;;ntp;accept;None;fwxcluster;Any;*Comment suppressed*
;;;;;;;;;;

The empty lines are there only to be more clear, I don't actually need them.

Thanks!