Here are some examples for you. (I’ve added “tags” to the diagrams, so if you want to know what a building is, just move your cursor over it and wait a second or two to see the description.)
The first example below is what I think you are describing. You have some industries along a road (I used a couple of breweries and jewelers in this example) that leads to your housing area. In the housing area, you have an architect, fire warden, temple, water supply, etc. When you placed a roadblock to keep the walkers from going into the industrial area, then the industries could no longer get workers.
In the second example, I added a road around the roadblock that passes by the “back” of the housing. The labor seekers from the industries will not pass through the roadblock, but now they have an access to the housing provided by this new road.
The labor seeker must pass within 2 squares of two occupied housing squares to get workers. The road in the third example would also pick up workers from the houses (if there is some city wide unemployment).
I like this last option because you can place gardens, small statues or shrines in the space between the road and the housing. This will help improve the desirability of the area, and can act as a shield against undesirable structures nearby.
[This message has been edited by VitruviusAIA (edited 03-13-2001).]