Bear with me, I'm trying to figure out how to word this question LOL. 

I like to try to order series books from the same person.. so if I'm ordering books that are available, how can I find the person with the most available in the series?

For example: Book One has 20 available copies. Book Two and Three also multiple available.

I order Book One and search the person's shelf. No other books in the series.  Now there are 19 other people with Book One... but how do I find them? Each time I try to order Book One it gives me the same person. I don't mind searching those other shelves.. but how do I find them?

I'll even try to order Book Two.. and search that person's shelf. Same problem and so on.

Am I missing something? Any suggestions?

I guess I'm hoping for a shopping cart. It'd be great to add all the availables and have it auto-request to someone that has the most.

I'm not sure, but you might be able to start a request, check their list, not close out the request and open another ad nauseum, leaving them all open but finishing before the hour buyer's-remorse-hold is over. Personally, I'd start with the lower availability books first since there wouldn't be as much to juggle.

You don't have to actually do an order, just start one. So once you hit 'order this book', the next screen will give you 'order more' on the top right and below that 'process this order'. Use 'order more'  to look at their shelf and if they don't have anything just back all the way out to the book detail page without hitting 'process this order'.

Don't try Book 1 each time.  Try Book 2, then look at that person's shelf and see if they also have 1 etc.  Then choose Book 3 and check for 1,2, and 3 on that person's shelf, Book 4, then book 5 and so on until you find the person who has the most books in the series.  After you order them from the person with the most books, you might want to PM the person and see if they have any more.  Sometimes people have ones that aren't posted or other unpostable ones you might want.

When the above strategies haven't worked, I've had luck posting a query for series-books in the Bazaar.  I always add that I'm not looking for a 'deal', and that I just want to order multiple books at one time.

I would start with Debbie B.'s suggestion.  Just ask in the Bazaar - if it's a popular series, you'll probably get a response and it will save alot of time messing around with ordering books, searching bookshelves, cancelling books, etc.    If you get no response in the Bazaar, then use the other routes.

If you can't get them through the Bazaar, in addition to the suggestions above, another way to do it is to search Boxer's shelves.  You do not have to be a boxer to search boxer's shelves - someone suggested this years ago in the forums and I just tried it to see if it still works.  Go to Box-O-Books under the Community tab, initiate a search for one of the books.  Once you have that, open a new tab and do the same thing with the next book and so on.  Then compare the lists of boxers with each book and see if there is one (or more) with all the books on their shelves.  Anything posted on a boxer's shelf is to be available to everyone for ordering through the system so you would just order from the shelf as you normally do for a credit each.  If you are also a boxer or join the BoB program, you could arrange a box deal without the credits but the other boxer would need to find something on your shelf to trade with you.

ETA:  I tried the boxer search with several Grisham titles and it resulted in several boxers having several of his titles available so it does work to search this way, it will just depend on the series you are looking for.

Exactly what Renee & Debbie B suggested.