AHK script using SetTimer and CustomMessage

I currently use a script which uses things like StepDelay := -9999999999 ; Set the delay to wait between steps global MessageList := [[0, 1], [2, 3], [4, 5], [6, 7], [8, 9], [10, 11], [12, 13], [14, 15], [16, 17], [18, 19]] Sequence: ; CustomMessage uses SendMessage. Different values are used depending on Index - see the ; function definition at the end. CustomMessage(Index) TimerSet := A_TickCount ; Record when the timer was started. This is used for the countdown SetTimer, Sequence, % TimerLength := StepDelay ; Set the timer for the next time Return Wheelup:: ; Fire the next step Controlsend,, {LAlt Down}h{LAlt Up}, ahk_exe [login to view URL] StepDelay := -99999999 settimer, wheeldown, off gosub, Sequence ;varzz=1 return Wheeldown:: StepDelay := -99999999 Controlsend,, {LAlt Down}h{LAlt Up}, ahk_exe [login to view URL] ;StepDelay := -99999999 if ((Index -= 2) <= -1) Index := [login to view URL]() - 1 else if (Index = 0) Index := [login to view URL]() gosub, Sequence Controlsend,, {LAlt Down}h{LAlt Up}, ahk_exe [login to view URL] ;varzz=1 return WheelOnOff(State := "Off") ; WheelOnOff turns mousewheel hotkeys on and off { Hotkey, IfWinActive, Sierra Hotkey, WheelUp, %State% Hotkey, WheelDown, %State% } CustomMessage(ByRef Index) { if (++Index > 10) ; Add one to Index. If Index is > 61... Index := 1 ; Reset to one SendMessage, 0x1330, MessageList[Index, 1], 1, SysTabControl321, Sierra ;TCM_SETCURFOCUS = 0x1330 SendMessage, 0x1330, MessageList[Index, 2], 1, SysTabControl321, Sierra ;TCM_SETCURFOCUS = 0x1330 } So, at the moment I use wheelup and wheeldown to manually toggle between the global messagelist, and I can also use the below two variations to put them on timers, in up or down directions. Up: Stepdelay :- 4000 gosub sequence Down: gosub sequence settimer, wheeldown, 4000 What I want to add to this, is a way to use the timer function, but only on specific messagelist entries. I'd also want it to go up and down through them, eg if I want [0, 1], [2, 3], [4, 5], [6, 7], then it will look like send 0,1 sleep x send 2,3 sleep x send 4,5 sleep x send 6,7 sleep x send 4,5 sleep x, sleep 2,3 sleep x sleep 0,1 sleep x send 2,3 etc etc Then I want a way of interrupting this and turning it off immediately, in the same way I change stepdelay, or turn wheeldown timer off in my above scenarios, I want to be able to use that command in different parts of the script.