Using library music in two different houses

I have set up Bluesound streamers in two different houses, with obviously two different wifi-lan networks. In both houses I have added my (large) music collection, using a network drive in one house and a USB stick in the other. 

It seems that as I move from one house to the other, I have to re-index the library to get access to the files. This seems a bit odd to me, and is most inconvenient. Do I do something wrong or is this "expected"? 

I use the same BleuOS app in the houses, using an iPhone or the Mac App on my iBook

Thanks for helping out!