At the moment I have 4 different documents from another program that I import into scrivener, using the “Import/Import and Split…” Separators. This works great, but it would be even better if I only would have to do this once. Is there a way to combine the Separators?
Do you mean that different separators are used within the source documents? If so, try doing a find/replace to a single separator before using Import & Split. There’s no way to enter multiple separators, but there other options like splitting by styles for Word docs. See section 9.1.6 on page 194 of the manual for more information.