If a group of people at work misses the Dhuhr prayer, should they pray it in congregation or individually?

It is permissible to make up a missed prayer in congregation, and the proof for this is what is narrated that the Prophet (peace be upon him) and his companions missed the Fajr prayer during one of their journeys, so they prayed it congregationally as a make-up.

However, one must be careful not to delay prayer beyond its prescribed time without a legitimate Shar'i excuse, such as forgetting or sleeping, because that is a clear violation of the Almighty's saying: ﴿Indeed, prayer has been decreed upon the believers a time-bound ordinance.﴾ And the doer of such an act falls under the general meaning of the Almighty's saying: ﴿So woe to those who pray, [But] who are heedless of their prayer﴾ meaning they delay them beyond their times.