I working on a system in Drupal 7 that is targeted on a certain domain (the domain plays no role, but all sites in the system have the same domain). I'm trying to make different sites work together more seamlessly.
The idea is that two sites should be able to work together by sharing their nodes, e.g. they want to share their calendar events. The problem is that the two sites are in seperate databases, which can't be changed. Two sites should be able to start or end the collaboration at any time they want. Some degree of realtime sharing would be nice. So that one site can update and event and the other will know within a realitively short timeframe.
I was hoping that a module for this already existed, but I haven't been able to find one. It seems to be a case of syncronization between the sites. Do you know a solution to this problem?