Warfare & Tactics

First off, yes I have used the search function and fitted an anti-thermal hardener to counter incoming flames! I can't find the answer to a specific case with the wardec/ally system. I've been looking at this dev blog from Inferno:

http://community.eveonline.com/news/dev-blogs/72742

It states that if a corporation that is an ally joins an alliance, then the ally status transfers to the alliance as a whole. OK, so if your corp is an ally in a war and joins an Alliance, the status travels up to Alliance level. So far I get that. But does it have to specificly join an Alliance while being at war for it to confer? What happens if your corp is in an Alliance already, offers to ally, and gets accepted? Does the war confer up to the Alliance, or can only the alliance as a whole offer assistance?

Thanks for your answers!