John Malone's international cable giant Liberty Global has inked another splashy deal, this time with the purchase of Multimedia Polska, Poland's third-largest cable operator, for around $760M in cash. Liberty Global-owned UPC Poland, already the country's biggest cable company, finalized the deal, which gives the company a firm foothold in the market and sees the combined operations reach more than 4 million homes and businesses the territory. "The acquisition will…