Thanks a lot for your comments and advice, now things are starting to get more clear for me. However, I have one more question. I have now completed a detailed level of analysis and I discovered the following.
Our company is having these domains (same structure as in these):
namegroup.com
name-group.com
When you go to either of these addresses, it is directed by using 301 to the following URL: http://namegroup.com/en/accounting-outsourcing-and-legal-services (no external linking root domains)
In addition, in the past some part of the link building has been made to http://www.namegroup.com (15 linking root domains), some to http://namegroup.com (1 linking root domain), some to www.name-group.com (6 linking root domains), some to http://namegroup.com/en/main (2 linking root domains). And now all is directed by using 301 to http://namegroup.com/en/accounting-outsourcing-and-legal-services (no external linking root domains). These pages have been the main page at the time these links were created.
It would make the most sense for me to start using www.namegroup.com as the main URL (as this URL has the most linking root domains), and then redirect all the rest here by using 301. And when possible, change the link in the rest of the linking domains to direct to www.namegroup.com
It is quite a big mess now, and I would like to bring some order and consistency here (also use in the future only this form). Why I am wondering whether I should make this, is that since I optimized the title tags and changed the URL for the current one (http://namegroup.com/en/accounting-outsourcing-and-legal-services) some weeks ago, we are ranking very well in Google for some of the most important keywords that we now have in the title tag and URL (we are in first page of SERP, in third and sixth place). I think it is mostly because of optimizing the title tags (but perhaps there is effect of the URL change as well).
Should I still do the change, and start using www.namegroup.com as the main domain, and redirect all others by using 301 there? What do you think?
If I would not change anything, and would keep the current main page URL, should I focus my link building for the URL http://namegroup.com or http://namegroup.com/en/accounting-outsourcing-and-legal-services? Somehow I feel like I would not like to focus the link building for the current URL, in case we decide to change it in the future (it is also quite long) and would prefer to focus link building for http://namegroup.com or www.namegroup.com.
Thank you in advance for your valuable comments.
Best regards
Sam