To Do Lists for others

[ger1073]

Hy there,
is the an app that can create a to do list for others.
I work with a couple of firms, and I have a lot of to-do's for them.
It would be perfect if I have an app that controls all of them.
Especially: I want a reminder if someone has not done his to-do in time, and it will create automatically a reminder email to this person.

is there existing an app who can do this?

Thanks for help.

Thomas