I have 2 kittens, almost 6 months old. No cat flap yet, am getting one soon. They're only allowed out in the day time...

There's a lot of other cats in our cul-de-sac, about 6 I can think of, maybe more. Most stay away, or come around once and again...

Should I be discouraging this cat from coming into my cats territory, will it upset them?