Can oscillating multi-tools be used for fitting pattress boxes
Bosch lists a segmented blade HM-RIFF that it says will cut grooves in porous cement, small cutouts in soft wall tile. I guess four grooves would make a cutout. A lot will depend on the thickness of the brick,.Are you looking to cut thru a brick veneer or the entire thickness of a conventional redbrick? I would try to get a similar material to practice or trial cut.  The width of the blade looks a little wide to cut the short sides. You may be able to make a series of long cuts then chip out the segments.