I think all of them can, but it also depends to which Slavic countries.
Greeks are friendly to Bulgarians and Serbs, but not to Macedonians.
Romanians are friendly to Serbs and Bulgarians, but not to Ukrainians.
Germans are friendly to most Slavs, but not to Poles and Russians.
Balts are friendly to most Slavs, but not to Russians.
Hungarians are not friendly to most Slavs, only Poles, Croats, Slovenes, Bulgarians and Czechs.
Austrians and Swedes to my knowledge, have no problems with any Slavs. We have had wars in past, but relations in general I think are good.
Moldavians probably don't like any Slavs, or don't care about those they don't like.
Hehe, hard to say.