Can we use email instead of UserID as the connecting attribute between leads and users? (detailed question below)

hello, I have a complicated request that I’m hoping you can help me with — we’re using email automation to invite “leads” to join our app, but are having issues with figuring out how we should configure the exit rules. Ideally, we’d like “leads” who convert in the sequence (i.e. install the app and create their profile) removed from the sequence so they are not sent an additional email telling them to download. However, it appears when someone converts, a duplicate profile is created in Intercom under “users” that are not connected to their “lead” profile. I believe this is because we are using UserID as the connecting attribute between leads and users, so my question is, can we use email instead? I assume that would eliminate our duplicate issue?

Next question, if we do that, how should we configure the exit rule to ensure people are removed after signing up for our app? Would we use “Signed Up” less than (more than?) some period of time-related to the length of the email automation?