The short answer is yes. However there are a number of secondary considerations. If the loads are in the same vicinty or panel, where the conductors can be grouped together through a single CT, they could be monitored by a single meter. The meter and CT would need to be rated for at least the equivalent total current. (40A x 3 = 120A Total) This would require a 200A rated meter and CTs.
Accuracy may be compromised slightly when multiple circuits are combined like this, so be sure that tight tolerances are not an issue.
Just to clarify, each hot conductor for a circuit would require a CT. A single pole load would use 1 CT. A 2-pole load would use 2 CTs, and a 3-pole load would require 3 CTs.
Could you have three loads measured by one meter?