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:

1. Create a Contact Collection from an Office 365 Distribution Group.
2. Click the drop-down arrow next to the Office 365 Distribution Group under Collection Preview.
3. Click the ellipsis next to the user you want to exclude.
4. 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.