Heres with commandline PERL:

$ perl -ne 'chop; split;
> if($_[0] eq "Group")
> { $group=substr($_[3],1,length($_[3])-2);$score=$_[6];}
> else{
> if($_ !~ /^\s*$/&&$_[0] ne "Score")
> { if(@_==2){push(@_,"","");}
> if(@_==3){unshift(@_,"");}
> $string=join(";",@_);
> print ("\n$group;$score;$string");}}' file_name


Assumption(s):
Your records can have only 4 elements at the maximum.
That is ,
record/blank record/blank record/blank record/blank
If you can tell me whether these are tab separated, I can help with a more robust code.