It sounds like your team is independently creating the same class model. I think this is a mistake, but even if you could turn off the class number, you would encounter the same merging problem for the class identifier (not visible on diagram).
From a pure xtUML standpoint, all you should need to guarantee uniqueness of a class is the class name and the domain name (as a referential attribute). BridgePoint doesn’t currently take this approach. (You can load the ooaofooa from the Welcome page.) Identifiers of model elements in BridgePoint are currently undergoing some revision, but I don’t know what the final form or timeline will be.
You could file this as an issue. I think it is valid. The class numbering is a vestigial element that probably no one would miss.