Shall can work but to me using the word "will" for the context to be definite or "can" if its a possibility

In common American English 'shall' is rarely used. However, in other locations/eras it would be the preferred word. Ask yourself who your audience is and if they prefer older English word usage.

"Shall" is normally used to express firm intentions. For example, "I shall do that!" Or "We shall win!" It does work in your sentence. It would work if the employees said, "We shall work the required hours! We want to help the company!" Hope this helps