Slitherine

Cavalry pursuing cavalry as the result of melee fail to stay in contact. However,
a BG of LH pursuing another routing BG of LH would contact the routing cavalry.
I assume you just do the usual one base removal as they are routers and don't
count it as a fresh combat? (Normally not so important, but it meant a general
was diced for and fell off his horse).

Rgds,
Peter

You assumed correctly

The rules, I think, state there is only one 'combat' type against routers, the base removal when a pursuer remains in contact at the end of a pursuit. So you have it correct.