Is it permissible to perform congregational prayers in places where passersby break their fast instead of going to the mosque during Ramadan?

Your providing of Iftar to those who are fasting is a righteous deed for which you will be rewarded, and your prayers are valid. However, praying in the mosque is more meritorious and carries a greater reward. If you are able to combine providing Iftar to the fasting with praying in the mosque, then do so. Otherwise, there is no harm for you to pray in your place as a congregation. Avoid praying in the middle of the road, as the Prophet (peace and blessings be upon him) forbade praying there, due to the dislike of the heart being preoccupied by people passing by and the inconvenience caused to them.