We are 8 building lessees in a bldg. The bldg and land was leased to us for 50 (since 1950) years with optional extension clause of another 50. Midway through the first lease the lessor did not collect rent and was untraceable . Since 1990 we have been staying in the premises without paying any lease rent. Someone who entered the building as tenant encroached on the common land around the same time and fenced it and claimed it as his. Now the original lessor has shown up in 2015. Can we ( original lessees) claim that we are staying by virtue of adverse posession ? Can the encroacher claim adverse posession ? In this case who can claim title to the land the lessor, the lessees or the encroacher ?