Yes, that is certainly possible. Testersuite is ready to use out-of-the-box but can also be fully configured to fit seamlessly into your way of working. It is possible to create all types of custom fields (text fields, dropdown lists, date fields etc.) for all parts (requirements, test cases, defects etc.). In addition, the workflows in Testersuite are completely flexible. Do you have a Premium subscription? Then you can even create multiple environments and configure each environment completely as you wish.