I'm not sure how SecureCRT is working and can be configured. The rebex component we are using in our product is capable of scripting automation and I'm happy to explore some new features in that area. If you can share some more details how other products are handling that or even better how you would like to have this feature implemented, that would be awesome!
It will probably not be available through key sequence tasks though - as this is more generic. It would be something you have to configure on the terminal connection (based on rebex) itself and it wouldn't really work with PuTTY...