When Importing into the Raiser's Edge
If you have multiple Salsa Engage records for one constituent in Raiser's Edge, you can still use Importacular to integrate your data from Salsa Engage into the Raiser's Edge. Importacular will look at each Salsa Engage record to see which Raiser's Edge record it matches (per your Criteria Sets).
As you can link more than one Alias of the same type, you can even use the Alias for Salsa Engage System IDs to link multiple Salsa Engage records to one Raiser's Edge record.
When Importing into Salsa Engage
Beginning in version 5.0, users have the option to export data out of the Raiser's Edge to import into Salsa Engage. You can still work with constituents who have multiple email addresses, but you will need to be conscientious as to what data you include in your RE Export output. You will need to think through which Raiser's Edge email addresses you want to integrate into Salsa Engage (will you limit to a specific phone type, just those marked as primary, etc.).
Click here to watch a video of ways to set up your RE Export to isolate the email address that you would like to use.