Our daughter is having a tough time napping at daycare and I'm looking for some perspective.

Background: we have a 21 month old and a 5 month old. 21 month old attends a Montessori school (since 10 months old). He struggled to nap there until he moved to the toddler room, at 18 months, and now naps fine. The toddler room has a common nap time, where lights are off and shades are drawn.

Our five month old is just starting in the infant room. The infant room has children from a few months up to 18 months. There is no common nap time, with the idea being that the children should sleep when ready and children at different stages have different sleep needs. The room is never bright, and the room is generally calm; but there aren't drawn curtains ever and there are often awak babies making a lot of noise. The caregivers do work hard to get the babies to nap: they have white noise, they will rock or hold the babies, wear or stroll the babies, sing, rub their backs. But several of the babies, including ours, seem to be struggling with napping.
Ours is still transitioning in, but I nervous--for both her and us--that this might last until she moves to the toddler room.

Also, the infant program at this school is only one year old, so they are still working things out. We really love it general, but naps are important!

I feel comfortable talking with the teachers about this, but I would like to have a sense of what is reasonable. If you have an infant at a daycare center, how do naps get handled? And how does your child do?