adding 1 new ad to ALL adgroups

how do you add 1 new ad to all of your ad groups

I want to splittest 2 ads and I have 300 ad groups and it doesn't seem like you can select all the groups and add the new ad to them.

I have adwords editor as well if that is better than trying to do this in the standard adwords setup.

there's got to be a way to do this but i'm not sure.

Can anybody direct me?

thanks