To link in with something or someone means to create a relationship between one thing and another or to say that two things are related. To link in can mean to connect with another person, another idea, statement or piece of work in a way that is useful or beneficial. To link in can also mean that something happened at the same time as something else, similar in meaning to tie in.

1. The point I'm making about our need to expand the business into new markets links in with the report we got yesterday which put our recent poor sales down to our lack of product diversity. 
2. When setting up the new factory in the town, the company linked in with the local council to ensure that the community was fully involved in the process. 
3. In my opinion, our new marketing strategy simply must link in with the public's desire for cutting edge technology if it is going to have any chance of being successful.

1. I am hoping to link in with another university to help me strengthen my research.
2. Several community organisations will link in to create a centralised location for the community to avail of support and resources.