Clan Castles Defense

I believe that players should have the option to make their troops stationed in their clan castles to defend their village or not. I cant say how many times I had all these nice troops in my clan castle just for some guy to attack me with a few troops and I lose everyone in my castle. I wish there was an option to say to defend village or to say ignore the enemy attacking. Also if we have that I think we cant have if the castle was destroyed that we would lose the troops, that would make the problem worse.