I found one software that does post for you but I haven't tried it, I have multiple accounts and post up to 20 bumps per hour but lately bumping doesn't bring post to top, maybe a
posts were too old, not sure. so I make new posts, but not too many per account per day and bump them for a few days, once per day. if your posts look spamy or too bussiness then it'll get deleted by the group moderators,