The Area being Modelled is :-
Asbestos Surveys
In a database for asbestos surveys, I would like to be able to keep track of all the 
different people involved, such as foreman, project leader, people who provide the 
key for the survey location, contractors, the person who will pay the bill, the 
people who should get the offer, assistants, and so on. 

This will in no time lead to a long list per survey. 

I have two question in relation to this: 
1. will this have a bad influence on the performance of the database? 
2. is my data model unnecessary complicated because of the table Involvement. 

If so, how could I organize things in a better way?