Dear friend, India is a secular country and we cannot allow any kind of religious activities in the business premises. If you give permission to one section of the society, the another may come up with their own requirement. So how many section's requirement will you fulfil?
Religion is personal matter and it has to be kept at the personal level. Let it not spill out to the office activities. If you allow that then the trend could be dangerous. It is not a question of small duration of time as such but of a doctrine. We must adhere to the doctrine that rejects religion and religious considerations during the duty timings.
Nevertheless, what is your lunch break timing? If some persons are interested then they may spare some of their time from the break and offer prayers. But that also should be discouraged.