@analienfrommarsy - to quote the great philosopher MC Hammer, “Ring the bell - school’s in…”. Here is some advice: If you are fortunate enough to get an interview with a Groton AO and to visit the school, you should not share with them that you are planning on “trading up” to Exeter. It doesn’t work that way. It is my understanding that Groton accepts around 14 boys and about 12 girls for their 8th grade class. It is extremely competitive - IMHO even more competitive than folks realize.
The 8th grade class becomes a very close knit community and remain through 12th grade at Groton.
I believe you should consider the good advice already shared from people on this thread. You sound like someone who could benefit from a Junior Boarding School experience here in the Northeast before applying to your target schools.