Some groups have held healing meetings, where someone who is acknowledged as having a healing ministry, (usually from outside the group) is invited to the organisation, probably during the lunch hour or during the group's normal meeting time. The person can be invited to speak, introduce their ministry and then to pray for people who have illnesses and wish to be prayed for. Another way is to simply allow those who come to be prayed for one-by-one by the healing minister. Clearly, care must be taken with advertising and with proper explanations of what is happening for those who might not be familiar with this type of ministry.
If advertised well, this can also be an excellent outreach event. When held at one CWG, several who were not Christians attended!
Remember that it is important to keep your managers and HR involved in what you are doing. In most cases your prayer activities and the means by which you advertise them will require permission from senior managers and HR. Make sure that you discuss what you want to do first, not after the event!