hard place situation

On my job, I have a certain situation where the customers requests clash with each other like there's a limited amount of time and I'm "overloaded" and so with certain runs being "time sensitive" , like one has dr. apt. the other a plane to catch at the airport, and a third going to work, and...

I have on the job what I call a scheduling conflict. where because of several people in one day ,and I can't be everywhere at once, sometimes on an overloaded day, one customer might take longer than expected, and start to cut into the time of the next one, who I also promised.That things work...