Hello all! I have the following problem. I need to calculate geo-distances between administrative division of Poland. Poland has three levels of division. It is easy to get a division from curated database like this:

level1 = Entity["Country", "Poland"][EntityProperty["Country", "AdministrativeDivisions"]];
level2 = AdministrativeDivisionData[#, "Subdivisions"] & /@ level1;
level2 = Flatten[level2];

To get geo-distances for the first level I can to this:

level1$dists = Outer[GeoDistance[#1, #2, DistanceFunction -> "Center"] &, level1, level1];

The above code takes some time to evaluate but nothing terribly long. However, at the second level of division there are 373 regions so if I use the above construction I need to calculate 139129 geo-distance. After cutting down all repetitions and distances between same regions there are still 69378 geo-distance to compute. Each call to GeoDistance[] takes about 5 second if DistanceFunction->"Center" is used and about 0.5 - 1 second with default options. This means that the computations should take about 15 hours in the best scenario.

Question: I think that the time required to do computation is mainly required for connecting to Wolfram servers. Hence the question is: can make this computation like a "transaction" in bulk with a single connection? Maybe I miss something and there is a better way of solving the above problem? Any help will be greatly appreciated!