adding a subpatcher / abstraction to a m4l patch?

hello dear community,
i'm trying to do something rather simple (?) —

i'd like to use multiple instances of the same subpatch within a m4l-patch/device. i want all instances of this subpatch to change in the main patch/device if i edit one of them — as if they were aliases. i assume i need something like an abstraction; an "external" max-file containing my subpatch.

how can i do that? where do i place the patch-file? which format will it have and how do i integrate it?

i've followed the turorial 15 (abstractions) but this doesn't help me alot.

i'd be gracious for any hint!
thanks