So I had an idea to take entire doujins and censor them with maybe a twist here and there. But I'm not sure of how this booru handles a page full of similar content/ pools like gelbooru would. Would I be able to group them some how and is that even allowed in the first place?

I havent found any sort of pools feature, or even a parent/child post feature on here. The only way you might be able to group them is with a tag unique to them.

Personally I think that they would clutter up, and a booru isn't really a great way to read a doujin either. Making an album on like imgur would be best as far as readability. Probably you could do something like upload the cover of one that's done so people could tag search it, then in the comments you could link the full album of it. We could also make a forum thread here to index them.

I know there's at least one person censoring doujins, they have a pastebin link of them somewhere.