I ran into a similar problem a while ago and I ended up doing it like that:
config file:

[one_server]
save_dir = /var/spool/bla/files

[one_server ABC]
dir = /var/spool/gugus/bla/save
glob = .
archive = p2gspsam.gsp_toAMS.save.tar.gz

[one_server XYZ]
dir = /var/spool/kw4711/bla
glob = .
archive = kw4711.bla.tar.gz

[one_server DEF]
dir = /var/spool/quatsch/bla/save
glob = .
archive = quatsch.bla.save.tar.gz
[download]

I then use Config::IniFiles to read the configuration:

my $cfg = Config::IniFiles->new( -file => "./$p_cfgfile" );
foreach my $group ($cfg->Groups) {
    ##  do something with: $cfg->val($group, 'save_dir');

    foreach my $member ($cfg->GroupMembers($group)) {
        ##  do something with: $cfg->val($member, 'dir');
        ##  do something with: $cfg->val($member, 'glob');
        ##  do something with: $cfg->val($member, 'archive');
    }
}
[download]

The concept of "groups" and "members" can be used to implement structured configuration as long as it contains only two layers.