The problem is that workshops, by their nature, can only look at small pieces at a time - a chapter or maybe two would be the maximum. You can (and should) edit each section thoroughly but be careful of losing sight of the bigger picture. The question 'Does the story work?' can only be answered by looking at the novel as a whole, not in little sections.
So, you need to find some people who will be readers. It's a good idea if they can be different to your workshoppers so they can come to the story fresh. It's good if they're writers too, but they don't have to be, so long as they read your genre. That's essential. Ask them about the story, ask them about how the characters are coming across, ask them about pace. Don't ask them to do a line edit - leave that for your workshop group.
I know several people who have spent years workshopping their novels, when IMO they'd be better off sending it out to readers. I understand why people do this - no one wants to ask a friend (let alone a book doctor) to commit several hours of their time to reading your novel until it's as perfect as you can possibly make it - but at some point it has to be done.
The perfect pattern would be: workshop until the first draft is done. Then send it out to readers, to check the story as whole works. Then back to workshopping to refine the text. Repeat as required.
Think of your editing as beautiful embroidery on a dress. There's little point in doing the finest work if the fabric of the dress is poor, or the style is wrong. Getting that right is what a reader will help you to do, and the workshop will help with the embroidery.