I dont follow you... can you describe your request better? You can set TYL System only for the first post in a thread in TYL System settings. No further modification is required.
Latest stable version is available on MyBB mod site; latest beta version for testing is available on our GitHub
Latest stable version is available on MyBB mod site; latest beta version for testing is available on our GitHub
[MyBB 1.8 Czech translation] [MyBB 1.8 plugins]: Prune old PMs + optimize DB plugin --- Thank you/like system