Ahh! You had to ask. No, it’s not simple.
The problem is: if you use loop cuts to stabilize the sides of the holes, those same cuts will also flatten the section of pipe the holes are in. So, you either have to move the cuts so the cross section stays circular, or design the cuts so they don’t extend much past the hole itself.
Take a look at this thread, it covers similar ground. GreyBeard probably has the best solution.