Ownership of common passage

Mr X sold two plots of land to Y & Z from his property leaving a 6 feet wide passage to connect these plots with the nearest public road.and for the use of Y & Z. X did construct a fence to separate this path from rest of his property.. Mr X has got separate access to the public road was not using the passage till his death . Now the heirs of X claim ownership of this passage and always make objections when Y & z try to get electricity and water connections through this passage and are not allowing them to do the maintenance of this path either.. To assert their ownership claim over this passage the heirs of X have made a new access to this path. Later Z divided his plot into two and gave them to his sons to construct houses.They all are using this path to have access to the above said public road. Leaving this path was a condition of sale these plots and has been mentioned in the land deed. Do the heirs of X still have the ownership right over this passage to make objections when Y & Z try to get electrical ,water connection and the maintenance of this passage.This is a municipal area and could the municipality have a ownership right of this path since it is being used by the members of three house holds.and so many other people like newspaper and milk vendors like.