Unless Russia have real time intel on the movements of these weapons transport, there is nothing else the Russian army can do but wait to be on the receiving end of these weapons.
Most people do not realize how psychologically debilitating are the Stingers to low altitude helos, and it looks like the Russian army will be experience that trauma again, once from Afghanistan when the US armed the mujahedeens and and today in Ukraine when the US will arm the resistance fighters. There is no ejection seat in the helo. Auto rotation is your only possible, not probable, survival. The Stinger is supersonic and most helos are usually below 10K flight altitude, that mean if the missile have a lock, you essentially die. Each Stinger cost barely $40K so even if it took two misses per flares and one hit per helo, that is a bargain to let the enemy know he will be flying into a death trap the next time he return. Once it is known that the Ukrainians are Stinger armed, every Russian helo pilot will be on edge. People have no idea how you will be emotionally and physically drained at the end of a sortie. Then when there are less air cover from the helos, Russian tankers will be at risk from the Javelins.