One would usually take hold over the other and cause it to weaken, whether through shear (from outflow) or assimilation of the weaker system. However, these two "systems" are 20 degrees longitude apart from each other at this time, making any impacts on each somewhat unlikely at this time. The biggest impact down the line could come if the first wave develops into a significant entity and churns up the waters behind it for the other system -- really, if we get two systems out there now, I don't think the waters would be able to support much more for awhile, but then again...this is the 2005 hurricane season.