MRR Hastati and Triarii

[badhabum]

A special rule seems to be often forgotten or overlooked  Separate triarii may only be deployed directly in front of the camp or directly and entirely behind TuGs of hastate and principes. Triarii must be in the same command as the hastate and principes that they are deployed behind.

We had a discussion about it and the definition of directly behind does not seem the same for everyone so what's the intend ?

Some players argue that directly behind implies a contact between the units . They must touch even if only corner to corner .

Others just that the Triarii are behind but no need of physical contact

Also what is "behind" ?

Behind a TUG or TUGS ( H hastati T Triarii )

HHHHHH

  TTTTT

or behind the line of Hastati

HHHH        HHHH
         TTTT

So as the group disagrees I ask here 

[nikgaukroger]

My take.

This:

Behind a TUG or TUGS ( H hastati T Triarii )

HHHHHH

  TTTTT

No contact between the triarii and the UG(s) they are behind is implied.