Zherculis,   You can indeed discover the same iDrac on multiple instances of OME, but I am not seeing any external documentation that would be of any help regarding it.   let me know if this helps.  
Hi Team,  I have a query about discovering one iDRAC instance in 2 different Dell OME  can one Dell iDRAC be discovered in 2 different instance of DELL Open manage enterprise ?  Can someone provide a supporting document for it 
Dell OME discovery of idrac