Is there anything else mentioned about the Future Victor 49 exercises on the Taurian border near the planets of Lindsay and Brockway besides the brief blurb about them making the Taurians go to full alert in 20 Year Update?
20 Year Update has one regiment of the Lexington Combat Group on each of those worlds. The only other units listed in the Altair PDZ is the other regiment of the Lexington Combat Group and the Ridgebrook CMM.
The ideas I've come up with are large conventional formations exercising with a mercenary mech regiment, a large aerospace and/or vacuum exercise is possible given the wording of "near" those worlds, or mech units present for the exercise, but not listed.