Assuming you are using Method 1 (UEB Accents and Contractions in Anglicized Words), you would use the standard UEB contractions you might expect. I typed both words into Braille2000 to see what would happen. That gave me P(en)(sion)e and (St)azione. The "one" contraction did not appear in the second word, likely because of pronunciation. If you used "one" in the first word, it would result in one extra cell.