So, my own kids are very close in age, two boys. They are pals. It warm my heart because they do things together and act like friends. It's nice! My sister had her kids with a wide spread in age. She found that her oldest, a girl, was like a little mama to her youngest. They remain close until this day. With boys, it may be a bit more where the oldest ignores the youngest. ha. At least that is my impression of boys. Until they are older and all are young men. I wouldn't curtail the older kids life for baby as babies and younger kids are adaptable to settings. My sister's youngest, the baby, just went everywhere. He napped at basketball games. he slept through sleep overs the older kids had, etc. My sister is 5 yrs/ 6 school years older than me and we because good buddies when I was in college and she was just out. Once we were both women, we had lots in common. Same will be true for all your boys. :>) good luck
P.s I have two girls and four boys and one on the way. So I've been through all the dynamics lol
I have all my kids close together and everytime I have a two year old and a newborn the two year old isn't always pleased. It's simple you keep them apart as best as you can if he tries to hurt the baby. After a while he or she will realize how much you like the baby and will want to participate. My two year old now let's me know if the baby is crying and likes to pet him and kiss him. Trust me the jealousy doesn't last too long. Don't take it to heart to much as long as you give them each a decent amount of attention it will work itself out.