Unfortunately, it's not directly possible to keep your folder structure for imports other than Zotero and Mendeley, but there is a workaround:
- In your other reference manager, select all references in a group/folder, and export those references as an XML file (for EndNote) or RIS/BibTeX file (for others). Give the files the same names as your folders so you can keep track, then repeat the process for each folder
- Create new projects in Sciwheel and give them the same names as your exported folders
- Select a project, then click Import references and choose the References option
- Import the XML/RIS/BibTeX file with the corresponding name to your project.
- Repeat the process for each project.