Yes, you can use CiraSync to exclude specific contacts as the source of a sync when using an Office 365 Distribution list as the source. Please do the following:
- Create a Contact Collection from an Office 365 Distribution Group.
- Click the drop-down arrow next to the Office 365 Distribution Group under Collection Preview.
- Click the ellipsis next to the user you want to exclude.
- Click Exclude.
Now, you can perform a sync using this new Contact Collection with the contacts you wanted to exclude as the source of your sync.