I've done work for a few condos. One property was through the management company. Somebody else topped trees. Residents got mad and the board said all pruning had to be done by a Certified Arborist after that.
The other is managed by the board....(mother of a friend sits on that board). They were looking cor someone to take better care of the trees than the lawn guys.
You need to figure out whether residents or a management company arranged for the services. If you get in with a good management company and do good work at a reasonable price, they are likely to stop bidding and just have you work on all of their properties if they don't have someone else already doing it. Which goes both ways...if they do already have a good contact, they probably aren't interested in your call...