I'm starting up a play-by-post Edge of the Empire pretty soon with some local friends, and while I'm familiar with the rules of Edge of the Empire there's one mechanic that I'm trying to find a solution for. Specifically, it's a keyword that the rulebooks use: "Each Session". For example, experience should be awarded at the end of each session, and obligations trigger once each session. For a campaign that doesn't have sessions, this obviously poses a problem.
It is difficult for me to imagine what a good point would be to introduce any elements that should be done each session. Perhaps it should be a certain number of posts? But then lets say this post limit is 20, and the player characters spend 20 posts role playing the same event? In other words, they make no physical progress during that time, so there's the potential for an obligation to trigger twice during the same event.
The other idea I had was to set the campaign up with some sort of "chapter" system, and then dole out xp and obligation consequences once each chapter. However, unless my chapters are incredibly short, the chapters would most likely span multiple sessions, if I were not doing a play-by-post.
I'm looking for suggestions on how to deal with mechanics that use the "each session" keyword. What have play-by-post GMs done in the past to overcome this obstacle?