Unfortunately this is not possible because PGC is using for Europe the information available in Open Streetmap (OSM). For Croatia there is only one adm level (6) available that covers the whole country,
Brodsko-Posavska županija, Grad Zagreb, Istarska županija, Karlovačka županija, Ličko-Senjska županija, Požeško-Slavonska županija, Primorsko-Goranska županija, Sisačko-Moslavačka županija, Splitsko-Dalmatinska županija, Šibensko-Kninska županija, Zadarska županija and Zagrebačka županija have adm level 7 or 8 available
7 Regions have no further adm level available other than 6 therefor the county map will not cover the whole country which is a necessity