Select Code to Download

#!/usr/bin/perl

...
s/\b(\d+:\d+:)(\d+)\K(; \1((??{$+ + 1}))\b)+/-$+/g;

print "$_\n";

43:1:1; 43:1:2; 43:1:3; 43:1:4; 43:1:5; 43:1:6; 27:3:7; 27:3:8; 27:3:9
+; 65:1:4; 65:1:18
43:1:1-6; 27:3:7-9; 65:1:4; 65:1:18