Regions like Northern Ireland should be open to RW no matter who owns it. For example, a normal RW can be opened which will flip control to Ireland, and vice-versa. You can also use an RW to return the region. However, a conventional attack on Northern Ireland will activate Irish MPP's if Ireland owns it, and UK MPP's if the UK owns it. Similarly, controversial nations like Kosovo can be added as a separate nation, only with this rule in place, where they will fight for survival in the RW.