How can you filter items that are not assigned to Hammocks

Hi all,

Can anyone help, I have assigned activitities to Hammock bars  based on work package list I have created and assigned a cost to the Hammock bars to produce a cash flow. I am however unsure if I have allocated each activity to a Hammock bar. I am therefore looking for a quick way to filter the activities that are not assigned to Hammocks wiithout having to click on each bar and check if I get the Remove from Hammock option which would mean it has already been assigned. I have checked the filters but cant see a way of doing this.

Any help would be appreciated.

Thanks

Chris