If you really need to, you can briefly unregister an event for all frames then re-register when done.
Lua Code:
local Frames={GetFramesRegisteredForEvent("ZONE_CHANGED_NEW_AREA")};
for i,j in ipairs(Frames) do j:UnregisterEvent("ZONE_CHANGED_NEW_AREA"); end
-- Do whatever you need here
for i,j in ipairs(Frames) do j:RegisterEvent("ZONE_CHANGED_NEW_AREA"); end
I wouldn't suggest doing this very often as it creates a new table each time it's run.
For the sake of simplicity, I didn't include a table recycling function to use in such case.