Recursive Link

I am trying to have the "Sales Invoice Line" table limited to ONLY the "Document No." where "No." = "DROPSHIP" The code I wrote for this looks like this:
"=NL(""Link"",""Sales Invoice Line"",""Document No."",""No."",""DROPSHIP"")"
However, it seems that placing this link within a link is causing an error.

This is the code for the actual table being generated:
=NL("Table","Sales Invoice Line",$E$10:$W$10,"Headers=",$E$9:$W$9,"TableName=","Sales Invoice Line","Link=Sales Invoice Line",$E$8,"InclusiveLink=Sales Invoice Line",$F$8,"IncludeDuplicates=","True")
The link in question is $E$8. This is the code that seems to have the error in it:
=NL("Link","Sales Invoice Header",,"No.","=NL(""Link"",""Sales Invoice Line"",""Document No."",""No."",""DROPSHIP"")","Filters=",$C$5:$D$6)I still need all the data from each document, so limiting the results to only the invoice line with only "DROPSHIP" will not work.

For what it is worth, here is the other link:
=NL("Link","Value Entry",,"Document No.","=Document No.")