Composite Tolerancing
The DMIS spec. has a tolerance called TOL/COMPOS which is the tolerance you require.

This has just been implemented by LK in the V5.1 release of the LK-DMIS software.

D variables
There is a similar functionality within DMIS. This is called the OBTAIN command (see page 286 DMIS V3.0 specification).

With this command you can extract values from measurement or tolerance commands and process them as required.

For example, to obtain the actual diameter from a feature measurement do the following

DECL/REAL,rDiam
rDiam=OBTAIN/FA(CR1),10

where 10 is the ordinal number of the parameter in the FEAT command that defines the actual diameter value.