Are double barrelled surnames permissable in Islam?

[Profoundbreakfast966]

I married a Spaniard and live in Spain. The system there is that everyone has two surnames - your father´s first and then your mother´s (but that order can be changed), and a woman keeps those surnames for life - she doesn´t change anyting at marriage. At first it was strange for me and my British friends for me not having changed my surname, but Spanish women were horrified by the idea of a woman changing to their husband´s surname - it seems to imply ownership to them.
Anyway, to get to the point - I am now totally against a woman changing her surname at marriage for the simple fact that with this new social network technology like Facebook, a woman having changed their surname makes it super-difficult to find your old female or Uni schoolmates you´d like to get into contact again - but it´s easy to find your male classmates. See? It´s sexist!