Is there a way to add an entire series of PaperBacks (ONLY!) to my wish list at once and have all of them put on Auto-Request but force them to be fulfilled in Series Order?

Like currently 9 and 13 of a series are available, and I am unable to add them to my Wish list because of this.

I want to be able to place them on my wishlist on Hold until I get the ones before them in the series.

I suggest you add them to your reminder list.  I use that for the books that are posted.

You cannot Wish for books that are available to order.  You will have to wish the others and just order the ones posted when needed.  If you don't want the WL ones to come out of order than put the ones you don't need yet on hold.  You will still move up the line but it'll skip you if you get to #1 for a book you aren't ready for yet.  I just wish all the ones my library doesn't have and take them in whatever order they come if it's a series I know I like already.

You can monitor the # posted for the available ones by putting them on your RL.  PBS will not keep one on hold for you until you are ready to order it, that wouldn't be fair to the book owners.   You just have to take your chances that they won't become WL in the meantime.

(belated edit to change WL to RL in my second paragraph)

Unless you're not sure that you'll like the series, I'd suggest snagging 9 and 13 while they're available.  Otherwise, Murphy's Laws of Book Ordering may kick in, the books will be on Oprah or something, and you'll be back in a Wish List for those too.  You might also be able to swing a deal, if they're both available from the same member.

That is what i have been doing, but it doesnt really help... :::shrug:::

Mary's suggestion sounds like your best bet.