How to unclog cast iron T drain for three sinks
Epilogue: I ended up replacing a one foot section of the drain pipe below the T with a clear piece of PVC pipe. I drilled a hole in the PVC pipe and covered it with a sliding rubber coupling. I can now run a snake up the drain pipe to the T area without removing the drain pipe. I also tried a water jet, but it was difficult to maneuver. I also periodically pour hot water and liquid soap down the sink drain to reduce potential blockages. Not ideal, but manageable.
Thanks for the suggestions!