Yes, you can combine any trait type within segments. All offline traits being used should belong to same data source. Also, select the profile merge rule in segment, that should have the same data source offline trait is linked to.
I am basically looking at segment rule. For example, I have age CRM data and I want to be able to create a segment where specific age has to visit the site. Basically, Age 18 - 24 AND Test.com (site visitor).
When setting up segments you are able to use Onboarded traits, rule-based traits, algorithmic traits and folder traits. A user can also creat new onboarded traits from Unused signals. please visit Signals Dashboard