@Adam514:
Can mechs and tanks starting in different territories invade the same empty territory and continue to the next territory? (mechs in east poland and tanks in ukraine going to west ukraine then bryansk)
No. Page 29 of the 2nd Edition Rulebook states the following under the description for Mechanized Infantry:
“A mechanized infantry unit must normally stop when it enters an enemy controlled territory. However, when paired one-for-one with a tank, it can make a blitz movement along with that tank. The movement of both units must start and end in the same territories.” (emphasis added)
Therefore, your suggested move would be illegal since both units did not start in the same territory.
EDIT: The above is referencing the Europe rules – there is a similar entry on page 26 of the Pacific rules.