My T212 is currently setup like that, it’s split across about 10 different mostly Vanguard tracker funds around the world.
But as other have said, unless you can predict the falls as they happen then all you’ll do is miss them bouncing back. If a fund loses 10% one year, it’s more likely to gain 22% next year and keep that ~10% yearly growth than it is to lose another 10%. If something’s cheaper than it’s average then you should put money in, not take it out. Conversely if it grows 20% in a year, that might not be sustainable and the next year might be flat.
If you can spot those wobbles in advance (e.g. in retrospect India did a fairly predictable -/+4% wobble due to the election) it could be workable. But at 6-9 months you’re probably looking at those losses already being baked in and it’s more a case of buy more and wait for it to to turn around.