How can I define a keyboard macro in Xfce-terminal

I use xfce4-terminal, and it's a great terminal emulator. For an application I run inside the terminal, I wish to define a macro key, so when I push the specific key, the terminal sends a bunch of keystrokes to the application. How do I do this? For example, if I push the physical F3 key, I want the terminal to tell my application I typed a,B,c and D as if by a human. It doesn't have to be F3, CrtlH, CrtlAltF9 or suchlike would be acceptable too. If the version matters, it's xfce4-terminal 1.0.4 (Xfce 4.18) I have read about editing ~/.config/xfce4/terminal/accels.scm, but this only seems to cover rebinding terminal functions, not creating macros. The relevant documentation doesn't really cover any of these topics - https://docs.xfce.org/apps/xfce4-terminal/advanced