Hi Squanto!
Perhaps if you would kindly provide us with a rough sketch (Not too rough I might add. LOL! ;) ) so that we could visualize better what you're attempting to describe here.
Also, If this welder cannot cite verbatim in D1.1 where it states that this is not allowed, and you get clarification from the EOR as to whether or not to allow it or not, then the issue is moot after the EOR's decision which will be final. Now there are a whole lot of unknowns with respect to the particulars regarding your query, so it's critical to make sure that you go over the specifics with the EOR since they're the one's engineering this job, not the supervisors or the inspectors because this is simply a decision that must be made by qualified engineer and not supervision or inspection...
That is, unless you don't mind becoming potentially liable for making a decision that was not your responsibility, or obligation to do so in the first place.
Bottom line is, get it clarified by the EOR (Engineer Of Record) before going any further which is the way to CYA in these types of situations - CAPECHE??? :)
Respectfully,
Henry