My group is going to pick up a manga from a group that posts their chapters on a separate site. They've done 0-9 but haven't uploaded it onto here. Am I allowed to start the manga off on ch 10 and refer the first 9 to the other site?
you can upload chapters in whatever way you want. No need to worry about it, we have groups that exclusively only release chapters way ahead of current translations and even those are allowed.