Normally trenches cannot be placed in building hexes (though there may be some SSRs that allow it with raised structures normally found in the Pacific or other specific instances). Also normally trenches only connect to another trench or to a Pillbox (hereafter referred to as a Bunker), however in the instance you cite trenches in adjacent terrain may also "connect" to Cellar Locations or the ground Level of a building without a Cellar per SSR. That is to say, a unit may move directly from WITHIN a trench to an ADJACENT Cellar or Building Location without first having to exit above the Trench counter to do so as is normally the case. This is pretty short and sweet, but I hope it answers your query or at least points you in the right direction.Playing ABtF. getting confused about trenches in building hexes. is this NA. ABtF SSR 17 mentions trenches connecting to building hexes.