Typically, when an EC parish is sharing a building, it’s borrowing the altar at a Roman parish.
It’s uncommon, but not unheard of, for EC parishes to allow missions of a different major rite (Roman, Alexandrian, Byzantine, Chaldean, Syriac, or Armenia) to start life borrowing their chapel. It’s less common to see it for different churches of the same major rite. But in the case of Romanian vs Ruthenian, they’re different recensions, and likely on different calendars; they will also have different customs about various non-liturgical activities. The Romanians are most likely looking for a suitable building.