The only common tradition somehow connecting both political creations was Orthodoxy and language to some extend.
Only Orthodoxy and language?Ask ConstantineK to give you some more complete information on that.
both countries are much closer to the Western Slavs than to Russians.
What do you mean both countries are...?You mean that the inhabitants of these countries are closer or sth else?Have you asked for example Ukrainians from Dnipropetrovsk or Symferopol or Belarussians from Minsk who they feel closer related to?