fetchXml multiple entities in CRM 4

hi All,

I have issue with fetchXml Query, I need display results from two link-entities, but I need condition "OR" between entities, because below query display only records which are in both entities,
I want records from "new_project_vendors" and "new_project_contacts".

var fetchXml = "<fetch version='1.0' output-format='xml-platform' mapping='logical' distinct='true'>" +
                   "<entity name='contact'>" +

                   "<attribute name='firstname' />" +
                  "<attribute name='lastname' />" +
 "<attribute name='contactid' />" +
 "<order attribute='lastname' descending='false' />" +

 "<link-entity name='new_project_vendors' from='contactid' to='contactid' visible='false' intersect='true'>" +
 "<link-entity name='new_project' from='new_projectid' to='new_projectid' alias='aa'>" +
 "</link-entity>" +
 "</link-entity>" +


"<link-entity name='new_project_contacts' from='contactid' to='contactid' visible='false' intersect='true'>" +
"<link-entity name='new_project' from='new_projectid' to='new_projectid' alias='ab'>" +
"</link-entity>" +
"</link-entity>" +

"</entity>" +
                   "</fetch>";



Thankful for any help I get.