Is a porch in a duplex considered a common area if they have one shared entry way?

[Linda L.]

I have a duplex that has one shared front door for the upper and lower units. After entering the main entry door, there are stairs leading up to the upper unit and another door to enter the lower unit. This main front door is the only way for the upper tenants to gain entry to their unit while the lower unit has an additional side door for entry. So my question is: Is the porch with the main door considered a common area? The lower unit tenant has lived there longer and has her furniture there with plants, but the upper unit has recently been leaving food out for an outdoor kitten on the porch  and so the two units have been arguing over who the porch belongs to. While the upper unit does have a balcony area, the tenants there have been maintaining the yard regularly and claim that an outdoor cat keeps the groundhogs away. We have a large family of groundhogs in the area and it is a concern. the lower unit tenant does not want the cat to be feed there at all and claims that it's her porch even though both mail boxes are there as well and it's the only entryway for the upper unit.  The lower unit has only mowed the yard twice in nearly 4 years even though it's supposed to be a shared responsibility. I don't know what's the best solution.

Thank you!