gotters

I would really appreciate some advice on th following:
I am developing a website which will function pretty much like a social network. I have already
developed a good amount of it however I am considering switching over to one of these pre-built
frameworks, either Elgg or drupal etc. with the hope that this could save me time and add
functionality easily.
The problem is that I have some very specific requirements as to how the system works. This is
an example of the structure I am building:

So lets say I have a network of headhunters. Every headhunter knows people looking for jobs
(call them personnel) and people offering jobs (call them employers).
So I want to login to this Headhunters social network and post the people that I know, both
Personnel and Employers.
So when adding someone under personnel - i add some details about the person as well as what
kind of job they are looking for.
Likewise when adding someone under employer I add some details about the employer and what kind
of worker they are looking for.
So now I have in my profile a few people under personnel and a few people under employers which
anyone else in the network can view my looking at my profile. I envision that they will appear
the same way you view someones friends in a normal social network but these people themselves
will not exist as users in the network. (as I will now explain)
Now another headhunter, lets call him Joe, will also logon to the system and add employers and
personnel. The system will then do some clever searching and if there is a possible match
between someone in my personnel and Joe's employers or vice versa, then next time I login I
will see a message in my dashboard indicating that Joe the Headhunter has someone in personnel
who is a potential match for one of my employers. I then can make contact with Joe to see if
this is a possibility. So too when any other headhunter adds an employer or personnel.

One last point - the network will be completely closed to the public. The only way you can
register with the network as a headhunter, and thereby view all the employers and personnel, is
if you are invited by another headhunter.

Ok i think thats the basics. There is a lot more to it but I think thats enough.
So I am concerned that something like elgg or other frameworks will be too rigid and not allow
me to create these kinds of objects through which the users (headhunters) all interact.

If someone who has experience with any of these systems can give me advice as to what framework
would best suit my needs, or if I should rather go at it on my own without a framework I would
really appreciate it!

Thanks so much