Except for open areas required for compliance with the following requirements for clearance between buildings, no front, side, or rear yards need be provided unless said district R-3A is in the same block with a use district which has yard requirements. In such cases, yard requirements shall be as follows:
Front yards: If district R-3A is on the same side of the street, the front yard requirements of said adjacent use district shall apply to that part of district R-3A within 100 feet of said adjacent district. No parking area shall be placed in such required front yard.
Side and rear yards: Where district R-3A abuts a use district which has side and/or rear yard meeting, such yard requirements shall be provided in district R-3A between said common use district line and any buildings.