Since you want to nofollow links between your sites, I presume the purpose of interlinking is for visitors only? How many sites are we talking about?
In general, you should be safe interlinking sites this way. I don't think you need to worry about anchor text either (with regards to the site the link point to). But I would also make sure the anchor text is "natural" (read: made for visitors) on the page from where you are linking out from.
But I am not sure what would happen if you interlink (lets say) 100 sites this way.