Single source that reflects on multiple emails?

Hi Everyone,

I'm relatively new with Marketo and am curious about the possibility of editing a single source that in turn, would reflect on multiple emails. I have to edit the footer which holds a disclosure in +50 emails and am under the assumption this disclosure will change multiple times in the future. Instead of having to edit each email individually, is it possible that I can build a single source which each email would pull from, that way I would only have to update the source once?

Thank you for your time.