Moving single events from Macbook to External Hard Drive iPhoto library

Hi Everyone,

I tried using the search option to look for the answer but did not quite find it. I am running low on space on my MacBook Air's hard drive (mainly due to photos, I think). I have read here how to move the entire library to an external drive, which I have no problem with. However, now that I have moved all photos to my external drive and freed up space on my laptop, I would like to periodically (maybe once every half year) move a few of my new events from my laptop to the external drive again to free up space. I don't mind doing it manually and I'd rather do without Time Machine since once I move the photos to the external drive, I delete them from my laptop. Is it okay to just drag (with my iPhoto open) highlighted single/multiple events from the iPhoto on my laptop and drop it to the iPhoto library icon on my external drive? Or will this erase the content on my existing iPhoto library on the external drive and replace it with the new events only?

Please do let me know if I'm being confusing... I would really appreciate your help since I don't want to jeopardize losing the photos I have saved on my external drive.

Thanks!