A lot of parents end up doing this, especially with twins. The problem is that every child has different sleep requirements, different nap
lengths, etc. If you want your child to sleep well and not go to bed over or under tired, you need to cater a bit to her own sleep routine and sleep needs. This can get a bit tricky the more kids you have, but if you plan ahead and organize things a bit (i.e. make some kind of routine), it shouldn't be too difficult.
Let's take twins for example. I highly suggest some kind of routine with twins (especially if you want to be sane by the time they are 6 months old!), mainly something that includes waking them up at the same time to eat (if one wakes, you wake the other) and then putting them down to sleep when they get tired (likely around the same time when they are very little, but this may change as they get older) and working on getting good nap lengths. Done this way, you might have similar naps and bedtimes. But there will likely be some issues. One twin may struggle with sleep when the other doesn't. One twin may be ill and have bad naps that day or need more sleep than usual. If this is the case, nap times and bedtimes may get pretty far off. For your own convenience (and sanity) you can try to balance stuff out so naps and bedtime happen around the same time (i.e. give the shorter napping child an extra nap so bedtime happens at the same time). Just keep in mind that you need to consider your babies as two separate children, with separate needs.
The same goes for children of the same family. You need to figure out what works for each child, not just for your children as a whole. Yes, this can get a bit tricky at times and may requires a few sacrifices, but it is also nice. You don't have to worry about frantically putting all the kids to bed at the exact same time. Instead, you can have time to spend with each of them individually as you are putting them to bed. Read a book. Give some extra special cuddles. If my husband is gone and I am doing this I will have one child play or read to themselves while I am putting the other to bed. Sometimes I end up watching 1-4 additional children and things still work out pretty well putting them to bed individually. I have to be more organized, but it works.
The best thing is that if you can get the timing right, your children won't be cranky and overtired when they are put to bed or under tired and unable to fall asleep. And they'll wake up nice and refreshed and happy. A win win for all.