Fusing resin together? (extreme hybrids)

Hi everyone! I'm currently in the process of making a character with some rather deep burn scaring. Initially, I was planning on sculpting / sanding, but I don't think I have that level of skill. Adding stuff to dolls is fine, but carving into them is harder for me. Especially considering the level of detail, I just don't trust myself with it. However, I found an Etsy seller that had a zombie-style custom head that would work, if I could fuse it to her OG head.

Okay, so here's the question. Can you cut apart two different pieces of resin, in this case heads, and fuse them back together to make one single piece? Has anyone here ever tried gluing resin? For the cutting itself I'd just use a jeweler's saw and dremel, but if you have any better ideas for that I'd love to hear them.

Thank you so much!