LinkedIn announced yesterday that you can no longer post a job for free in a LinkedIn Group.
The Jobs tab is now comprised of two parts;
These are jobs advertised on LinkedIn (directly from paying employers) that match key words specified by the group manager or that have been shared into the group by any of its members.
If you are a LinkedIn Group manager, you should look into setting up this keyword search ASAP otherwise your jobs tab will probably be empty.
If your company already advertise on LinkedIn, this is great because you now have more exposure for your jobs. You can push your jobs out to relevant groups you are a member of yourself. To share a job into a group, simply use the share options on the top right of the job ad page.
This is free.
I would guess that LinkedIn Group managers will be more likely to mark your job ads as spam if you post them here too brazenly, so be careful.
There is nothing to stop you starting a career discussion about where you might the perfect candidate for your latest vacancy though.