To include or exclude values from a lookup, you will require a custom filter.
For example, you may wish to exclude an absence reason from selection in a workflow.
Due to the complexities involved in implementing these changes, it falls outside the scope of support.
While support are not able to assist you in the creation of custom filters, our consultancy team can offer you assistance with this in the form of training or implementation. This may incur a cost.
If you are interested, please contact your Account Manager, who can arrange this for you.