This question is posed more often than you may think.  Several factors affect cellular signal penetration into buildings: building material (metal, concrete, wood), wall density, number of windows, and building height.
Metal buildings will shield the signals, concrete buildings will shield less so, but it depends on density, and rebar (wire mesh is worse for signal reception), and wood buildings will attenuate the signals less than the other two. A metal building with many windows will pass more signals than a concrete building with only a few windows. Height is also a concern. Cellular antennas are made to point downward, or down tilt. I work on the 33rd floor of a high rise, and my reception is spotty at best.
If cellular coverage inside a building is critical, I would talk to your local cellular provider about installing a cellular repeater, or micro-cell, within your building. Most major providers will conduct a survey of your building if you are considering this.
If considering cellular coverage for a new building, I would add the micro-cell into the construction cost and be done with it.

Also contact Andrew Corp and explain your requiremnt and ask about Radiax coax type products (www.andrew.com).

If indeed you mean "enhance", generally, the answer is no. THe best radio reception you can get is point to point with no obstructions in between (including so-called free space). Thus, if a buidling is in the line of sight of the two antennas, then it will interfre with the radio paths and degrade, generally, the reception.