Maybe, but you'll need a lot more than one IC weapon, which will usually be the BTs first target anyway. Moving and shooting up to 3 times before it's opponent can do anything assures the INF/Titan combo is in any position it wants, particularly if the INF come through a portal. Not saying it's illegal, but it certainly provides an edge. Barrage weapons aren't the answer, the Titans too powerful to ignore, can't assault it or what it protects as it then has multiple massive strikes and unlike others, keeps it's holofield, neither is just shooting at the Titan. Even if you get lucky, the rest of his army isn't fired at so it goes where it pleases.
While legal, a Titan getting +1 to hit in a ruin seems a bit dodgy considering it's size.
I''m sure a better mind than mine will find a solution, but the combination of all these Eldar special rules is beginning to take the fun out of my games. I'm not playing, just reacting.
I'm probably just over reacting, and if so, I apologize.