The key word that I would keep is reception. This succintly characterizes the type of event. The word drinks is implied and adds no additional semantic value.
It appears that you would like to give your prospective attendees an idea of what the purpose of the reception is. There are many avenues you could take, but perhaps consider something like:
- XYZ Organisation Introductory Reception
- XYZ Organisation Welcoming Reception
- XYZ Organisation Initial Reception
- XYZ Organisation Opening Reception
- XYZ Organisation Inaugural Reception
- XYZ Organisation Kick Off Reception
EDIT: Given the context of an established neighborhood church in a financial district, the following suggestions are added:
Perhaps you can consider additional phrases such as:
- Organisation XYZ Meet & Greet
- Organisation XYZ Community Mixer
- Organisation XYZ Neighborhood Reception
- Organisation XYZ Community Reception
- Organisation XYZ Community Outreach Reception
Given that it's a church, you could also jazz it up and give it a fun title, like:
- Organisation XYZ "Neighborhood Joy" Reception
- Organisation XYZ "Good Neighbor" Reception
- Organisation XYZ "Love your neighbor as yourself" Reception
In a less formal setting I would suggest phrases like "Meet Your Community Night," but in a financial district that might be too informal.