Sibling rilvary b/t Littles?

[The People]

We have a whole new group showing signs of slipping into the light. We have known about Fear for many years, Peter as well. But there are Paige and paper who are about 4 but not twins. Paper is exiting first (we have a trend that, when an area is ready to be explored a child comes out first. Anyway, she annoys the heck out f Two who thinks she is laughing at her. As well, Paper has inserted a few sentences into Two's monologues. We can tell because their voices are different and they are about the same age cognitively.

Anyone else have this? I don't mean teens and adults who disagree with each other's behaviour. Just two little kids picking on each other. Only Two just rants because "I was here first!"