How Do I Delete One Of A Pair Of Records.

I have a table, gdbdoc,  that contains record-key pairs, linking records in another table.   There is no significance in the order of the link: if records A and B are linked, then I don't care whether the link is A -> B or B -> A, and my normal query logic is
     SELECT ... Where DCIindiid = A ...
     union
     SELECT ... Where DCILinkid = A
(DCIindiid = key1, DCILinkid = Key2)

The link-creation process normally checks whether there is already a link in either direction.  Thus before creating a link A->B the logic checks to see whether either the A->B or B->A link record exists, and a new link is not created if the link already exists in either direction.  However recently one of my processes bypassed the reverse-link check, and I've ended up with a few hundred cases where there is both an A->B link and a B->A link. 

If I run a query: -
      select gd1.* from gdbdoc as gd1 join gdbdoc as gd2 on gd1.dciindiid = gd2.dcilinkid and gd1.dcilinkid = gd2.dciindiid

this displays all the records where one record links A -> B and there is also another record that links B -> A. 

How do I write a query to delete ONE of the pair of duplicate records?  I have two problems: -

Problem 1:  Table gdbdoc is keyed on (DCIindiid, DCILinkid).  Both guids are needed to create a unique key, and the table does not have a single key field.  You can't write
    DELETE gdbdoc where DCIIndiid, DCILinkid IN select gd1.dciindiid, gd1.linkid 
                            from gdbdoc as gd1 join gdbdoc as gd2 on gd1.dciindiid = gd2.dcilinkid and gd1.dcilinkid = gd2.dciindiid

as the DELETE ... SELECT ... syntax only seems to support a single returned value.  

Problem 2.  If we solved problem 1, we would (I think) delete BOTH the A->B link and the B->A link , whereas I only want to delete one of these links.

Afterthought:  Problem 2 seems easily solvable:  add "Where gd1.DCIindiid < gd1.DCILinkid" to the DELETE ... statement.  Although the concept of "<" doesn't really mean anything with a guid, this is accepted by SQL, and halves the number of records returned by the select.  Obviously I don't care which of the two links (A->B or B->A) is deleted.

Regards, Robert Barnes