Religious coexistence is accepted in Islam if it aims at creating a peaceful environment for different Religions followers. But it is not accepted if its purpose it to come up with a new religious framework.
Inter-communications with other religious groups.
Religious coexistence is an ambiguous term that means several things, including peaceful coexistence between the followers of different religions and agreeing a formula that ensures the common interests of all groups, particularly those living in the same regions or having common interests that require their cooperation. It may also mean trying to concoct something out of different faiths, or putting together a common religious framework that dilutes the distinctive beliefs of different religions.
Please refer to the earlier question, ‘Interfaith Dialogue’.