Dear Folks -
(Hi Kenji!) Ever since a rule (TNE, I think) that standing near to an intense electrical field can disrupt psionics, I've had a house rule that sending a trickle charge through your ship's jump field mesh creates a psi-shield for your ship. It doesn't stop psionics _inside_ the ship, just a barrier on the surfsce.
To balance this ability, I added a couple of drawbacks. First, the engineers job becomes harder - they have to roll to maintain the field. Second, you have to drop it to use your_own_ psionics. Finally, it gradually degrades the lanthanum grid, increasing the cost of annual maintenance. (It probably wouldn't, really, but I have found that the hip-pocket nerve is a good stick to use with players. "Do we really have to fire - you do know how much that missile costs?!!"