There should be a way to reserve one of those IP addresses to tie it with that device so that the router will always use it when the device requests an IP address.
E kwesịrị inwe ụzọ ị ga-esi debe otu n'ime adreesị IP ndị ahụ iji kee ya na ngwaọrụ ahụ ka onye na-ahụ maka redire ga-eji ya mgbe mgbe ngwaọrụ ahụ na-arịọ adreesị IP.