You can wash them all together, because the Jacquard tie-dye kits contain good Procion fiber reactive dyes. It's only Rit all-purpose dye that must be washed separately.
After you have allowed the shirts you dyed with the Jacquard kit to sit for 24 hours, all of the dye molecules have fully reacted, either with the fabric or with the water. At that point, it is completely safe to dump everything in the washing machine together and wash them. I always wash them first in cool water, together, but you've already done this step by rinsing them individually in the sink. The nest step is to wash them all together in HOT water, 140°F or higher if possible. It often takes two hot-water washes to get all of the excess dye out.
Only hot water will remove the last bits of unattached excess dye. There is always excess dye to wash out, with this type of dye. Once you've gotten it all out, it is safe to wash the shirts at any temperature with even white clothing. If any dye transfer occurs between shirts at this point, hot water will wash it out.
If you wash your tie-dyes out after only four to six hours, some of the dye may still be active. At that point, it is not safe to wash different colors together. It is safe to wash all of the different colors together only after you have allowed plenty of time for all of the dye to react. In a room that is 70°F or warmer, twenty-four hours is plenty.