Is it safe to use rel nofollow on my sites pointing to each other?

I have 6 websites, all from the same niche, I would like to add a top bar on the home page of all 6 sites, with everyone's domain names, so that each website points to one another on the top of these sites:

Our site network: domain1 domain2 domain3 domain4 domain5 domain6;

If I use rel nofollow will it leave me safe?

I remember that years ago I did something like this without using nofollow, I saw the websites being harmed! I was practically interpreted as blackhat by having "a menu" that points to other sites of mine! A relevance fell a lot! Just nofollow is enough? Is there anything else I can do to make sure you do not get me wrong with search engines?

<div style="text-align: center; background-color:white;">
<span style="font-weight:bold">Our Others Websites:</span>
<arel="nofollow"href='domain1dotcom'target='_blank'> domain1 </a> |
<arel="nofollow"href='domain2dotcom'target='_blank'> domain2 </a> |<arel="nofollow"href='domain3dotcom'target='_blank'> domain3 </a> | <arel="nofollow"href='domain4dotcom'target='_blank'> domain4 </a> | <arel="nofollow"href='domain5dotcom'target='_blank'> domain5 </a> | <arel="nofollow"href='domain6dotcom'target='_blank'> domain6 </a> | </div>

Remember, I want to leave this topbar on all webistes. This can lower relevancy of my websites, nofollow is very safe for not only because it does not vote, but that it really protects me, to have 6 external links, on all websites will I be prejudiced?
thanks all.

 

search engine not consider no follow links so it's safe but Balance your Inbound and Outbound Links.