Saturday Walkers' Club
Have you considered making this like a blog where you have guest posts on different topics relating to walking holidays - but obviously not posts by commercial companies. The Independent Hostels website does something along these lines. Some individuals have lots of experience in organising trips away (on a voluntary basis) for walking clubs, and may be interested in contributing. The posts could be on topics such as the practicalities of organising a group trip, where and when to go, experiences of group trips in different places etc etc. For example, my walking/cycling group (Central London Outdoor Group, http://www.clog.org.uk) has around 20 to 30 trips away every year.