This document explains how to configure contains search. This allows to do a contains search on fields referenced to this table.
1. Disable the glide.ui.ref_ac.startswith system property (Set this to false).
2. Navigate to User Administration > User Preferences.
3. Create the preference "<referenced table>.autocomplete.contains"
4. Set the value field to true.
5. Set the system flag checked and save the record.
6. Log out and log in