(i) = between, among.

intercēdere = come between.
intellĕgere = pick among, perceive.

(ii) = breaking a continuity.

interclūdere = shut off, blockade.
interfĭcere = destroy (lit. put between).

OB-, OBS-, OC-, OF-, OP-, O-, = against, on account of.

(i) = over against, before (as an obstruction).

offendere = strike against.
oblŏqui = speak against.

(ii) = towards, with the idea of favour or compliance.

oboedire = hearken to.
obsĕqui = follow compliantly.

PER-, = through, along.