Can I somehow include a sub-Makefile without creating an impicit rule for it?

Honestly, I want to control, when is this sub-make rebuilt. To my largest surprise, any time if I use an include generated.sub.Makefile, it also tries to rebuild-it and then re-read my whole Makefile structure. I do not want it. I know what is in generated.sub.Makefile, and I do not want it to be rebuilt, except if I say so. I do not want it to be rebuilt only because I included it. The goal is, generated.sub.Makefile should be rebuilt always if I want to, and never if I explicitly did not command it. Can I somehow do that?