Installing grills

hello sir,

iam from hyderabad, in our appartment HMDA building total 5 floors,

each floor has 3 flats,  1■    lift    2■   stairs     3■

both 1 and 3 corner flats installed  grills and they closed vth gate and in grills they kept some plants

one of the middle flat guy in 3rd floor installed grills infront of maindoor

now all r requesting him to remove it, 

I want to know can corner flats have right to install the grills as they r not allowing middle flat guy to install