You can always use "tie", or no separation+rough interaction. It depends what you are looking for really. There are 2 things to consider:

1) If you want stresses at or near your connection, model it accurately don't use approximations

2) Be aware how many degrees of freedom your elements have, and constrain/fix all of them. For example don't just pin beams to solids, as they won't prevent the nodal rotations, and you will get singularity and no solution.

Hope this helps,

David