The 13th Austrian Regiment was a Territorial Army unit raised in Olomouc, it fought on both the Russian and Italian fronts during WWI. During the fighting in Russia about 60% were captured or changed sides, eventually forming the Hanacka Regiment (6th Pluk) and gaining battle honours at the Battle of Bachmac where acting as rearguard they successfully held back the German pincer movement, allowing the Czech Army to escape along the Siberian railway which they held allowing the Allied Armies to advance into Russia via Vladivostok. They only returned home in 1920, but carried back much treasure given to them by the White Russians.
From an exhibit at Praga18 I learned that the Italians also allowed their POWs to form a Czech regiment to fight on the allies side. Using fieldpost number 52 after the end of the war they patrolled the Slovak-Hungarian border. More post to look for!