They can be developed together, but the times give in the Massive Development Chart:

http://www.digitaltruth.com/devchart.php

are different for Tmax and Delta100 -- at ASA100 in D-76 1:1, 12 min and 11 min respectively. I think it would be wise to develop them separately, determine the best times for each, then decide if you want to cut corners by developing them together.