The LOT website keeps telling me that there are no flights from London to Warsaw on my dates in September! For London to Minsk, there's an over night stop each way. BA don't get me to Warsaw in time for the LOT flight.
Lufthansa takes you to Vienna and then on Austrian, or rather Tyrolean. Going out on Tyrolean gets you there very late at night, and coming back means either leaving the meeting before its finish (dangerous, 'cos things get slipped through right at the end!) or staying an extra night.
Other airlines (e.g. KLM) take you somewhere to change onto Belavia.
Trains don't offer anything either......