If I always post the links from the same website in the same groups

It's not very good, right?

Maybe the master of the groups will notice this situation?

No problem with that. You can post same link in same group. Just only admin of the group can delete the website link if it won't meet their TOS of that group.
Thanks mate

Depends on the group mostly, some are really active and permissive, others are not that active ( so your posts will appear one after another and raise a flag) and might be stricter. You should use goo.gl or another minifying service to hide your main url anyway, so unless someone clicks the link he won't know you're advertising the same site.