Need Suggestions on Potty Training in a Small Daycare

I am extremely blessed to work in a small company that opened a daycare for its employees.  We have run into a few hurdles along the way:  dealing with different nap schedules, different discipline techniques, and negligence, to name a few.  Currently, there are two toddlers and one infant in the daycare and the issue we’re baffled by at the moment is that of potty training. Teaching bear to go potty

Here’s the situation: The daycare has two rooms, one playroom and one sleep room with a small closet, which are connected.  There is one provider with the children at all times.  The bathroom is down the hallway, making it difficult to take all three children if the older toddler, who is potty training, has to go to the bathroom.  Right now, we have a potty chair in the closet (in the sleep room) which is fine except for when either of the other children are sleeping.  We don’t want to put the potty chair into the sleep room for sanitary reasons.  We thought about putting the potty chair into the hallway, but since it’s an office, men are often walking the hallways and we don’t want out little ones half naked around them.

What to do?!: We really need some advice!  Is there anything that has worked for you?  We can put the two kids in their pack-and-plays while the older one goes potty with the daycare provider, however, if the potty process takes a long time (right now it takes @15-20 minutes) this is not a viable option – we don’t want the provider to leave any of the children unattended for that long.  Help!