You can advertise on a server wide scale. You'll need to find out what Dwarrodelf's player-created general chat channel is, but it's most likely to be GLFF. Join that channel and try it out there.
More often folks will advertise in the /ooc channel in the regions occupied most by new players, like Bree, the Shire, and Ered Luin. As long as you don't make more than a posting every 5 minutes or so, no one will be upset. I've even seen advertisements in level-cap zones from time to time. Be polite and not spammy and you can advertise this sort of thing in-game anywhere.
Good luck with your new kinship!
<<Insert clever sig here>>