I think a line must be drawn somewhere, it is not the first and only case why someone might want or need to have several devices with the same IP.
Only as examples:
http://forum.mikrotik.com/t/access-multiple-devices-with-same-ip-address/106788/1
http://forum.mikrotik.com/t/connecting-to-multiple-devices-with-same-ip-address/159052/1
http://forum.mikrotik.com/t/map-devices-with-identical-ip-to-external-ip-based-on-port/180074/1
Maybe one could start with the assumption that a request for help/assistance from a new member might (even if it is a remote possibility) be not completely crazy and I am pretty sure that it is perfectly possible to ask for the context/reasons/etc. without implying that the new member is crazy, ignorant or both.
Have a look at the topics linked above, they might represent (it depends if you are running Ros6 or 7) a possible solution, or at least give you some ideas to experiment with..
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