import re
p = re.compile(r'\bobject-group\b\S*(?:\s+(?!object-group\b)\S*)*')
test_str = "object-group network FTP\n description FTP Access\n network-object host BCD1\n network-object host BCD2\nobject-group network NTP\n description NTP Access\n network-object host ABC1\n network-object host ABC2\n network-object host ABC3\nobject-group service sample_service tcp\n description Ports 1 2 3\n port-object range 80 81\n port-object eq pop3\n port-object eq imap4\n port-object range 443 444\nobject-group service 8080 tcp\n description Servers"
print(re.findall(p, test_str))

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