We need some help with our work schedule?

I work in a very busy dental clinic for kids. Recently at a meeting, we ( the assistants) would like to come up with a schedule so that we ( all 8 assistants ) would not have to work late everyday and still be able to get our 40 hours per week. Our hours of business are monday and wed 9a.m. to 8 p.m tues and thurs 10 a.m to 8 p.m. and Fri 9a.m. to 5 p.m. in order to come up with a scheduled that works we have to have 1 assistant per column. There are 7 columns on our schedule. Anyone out there willing to figure out this puzzle?We'd really appreciate it.

We need some help with our work schedule?
I'm sure I can come up with something, but I need a bit of clarification. I can get the 5 days per week, but what do you mean by 7 columns?