Question on retreating land units

[Sihrtogg]

Under LHTR rules:

Land Combat Withdrawals (excluding amphibious assaults) :
Retreat all attacking land units in that combat to a single adjacent friendly territory from which at
least one of the attacking land units entered. All such units must retreat together to the same
territory.

When retreating all attacking units to a territory, is it required that at least one unit of those retreating units came from that territory, or can all units which came from that direction be dead and still allow the other units to retreat there?
LHTR is usually very explicit, but in this case neither is explicitly written down. In the above quoted text the first instance of ‘attacking land units’ refers to ‘surviving attacking land units’ because I doubt I can actually retreat ‘all attacking land units’ (even the ones dead). But should the second instance of ‘attacking land units’ be read as ‘attacking land units (including the ones killed in action)’ or also as the same aforementioned ‘surviving attacking land units’?

For example:

Japan attacks Kazakh (defended by 4 Russian inf) with 3inf from Sinkiang and 4arm from Persia. If the Russian inf score 3 hits and Japan scores less than 4 hits, can Japan choose 3 inf as casualties and retreat 4arm to Sinkiang? Or must he choose 2inf + arm as casualties to be allowed to retreat inf + 3arm to Sinkiang?

[Krieghund]

It doesn’t matter if the land unit survives to retreat or not.  Just its having moved into the territory establishes the retreat path.