Using VCAC service blueprints to call VCO workflows

Hello,

Our situation is that we are creating service blueprints in VCAC to invoke workflows in VCO.  One example is to destroy a user, which deletes a user from AD.  On the Blueprint Form tab, we have the input parameter as a drop-down type (to obtain an object of type AD:User).  We would like to have the values displayed be alphabetized.  We would also like to be able to exclude certain values from the list.  For example, we do not want an administrator user to be able to be deleted if they are in the same AD container.

Thank you for your assistance!