All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
Apparently, the reward of offering Iftaar for the fasting Muslim is not exclusive to the poor because the Prophet, sallallaahu ‘alayhi wa sallam, said: "Whoever provides a fasting person something with which to break his fast will earn the same reward as the one who was observing the fast." [At-Tirmithi] The Prophet, sallallaahu ‘alayhi wa sallam, did not say, "Whoever provides a fasting poor person..." The term "fasting person" includes both the rich and the poor.
However, the ruling of eating from the Iftaar organized by Qatar Charity depends on the conditions stipulated by it. If you know that the Charity organizes this Iftaar for the poor and needy people only, it will not be permissible for a rich man to break his fast (with the food served) in its tents. But if the Charity does not make it exclusive to the poor and needy people, the rich will be allowed to eat from its food. Iftaar which is arranged by such charities is often financed by charity money that people pay for the poor, so, we do not find it permissible for the non-poor people to benefit from it.
As regards inviting Muslims to have collective Iftaar in Ramadan or at any other time, this is permissible since Islam calls for fostering affection, love, and strengthening Muslims' relations. Thus, if a Muslim invited people to a collective Iftaar, there will undoubtedly be much good in that. It was narrated on the authority of ‘Abdullaah ibn Salaam that the Prophet, sallallaahu ‘alayhi wa sallam, said: "O people! Spread Salaam and serve the food (i.e. feed the poor)." [At-Tirmithi] It does not matter whether the one who invited for this Iftaar is one of the attendees or anybody else, for this creates harmony and love among Muslims and calls them to compete in goodness. No doubt, these are part of the great objectives of the Sharee‘ah. However, in case these gatherings lead to much waste of time or involve gossip, then it is preferable not to attend them.
Allaah Knows best.