Territorial Cats
I have 2 cats, both about 10 months. I took them in when they were about 7 weeks (found them in an alley) and bonded closely with both of them. They spend most of their time outside. I sit with them on the porch (they like sitting on my lap) and take them on a walk every night (they follow me around). I've always been fond of forming bonds with all cats, strays, domestic and ferals so that's what I've been doing with the cats around the neighborhood. Recently, they've been becoming incredibly territorial. When a cat goes anywhere near me, even if it's just on the same road as me, they become defensive (defensive stance, growling, hissing, etc.). They won't allow any other animals in general to interact with me at all excluding my hedgehog who they grew up around. Is there anything I should do about this? Should I stop interacting with other cats or teach them to not be so territorial? They don't do it as bad to people but they still get slightly defensive, often standing in front of me or growling if someone tries to interact with me.
Side note: Just to be clear, they love being outside. I originally started letting them out because they had separation anxiety. The girl's anxiety (Iselda) was so bad that I couldn't leave a room for more than 5 minutes without her yelling and looking for me. Being outside has helped them a lot with it. They often stay in the yard, occasionally going elsewhere but never leaving the alley.