Two Keplerian closed orbits always intersect:
Source: Astronomy SE answer by Flater
As seen from Earth, Venus appears larger than Mercury; this makes sense because Venus is both larger and closer than Mercury (as measured by minimal distance; by average distance all planets are equally distant), but can also be readily observed by comparing solar transits for either planet (or wait for 26 July 69,163, when both transit simultaneously).
Unless prevented by orbital resonance, that means that sometimes, Mercury should be eclipsed by Venus (occultation) when, seen from the Earth, Mercury is exactly behind Venus; and Mars should pass in front of the outer planets occasionally, but I'm not sure which body appears larger from Earth (Mars or Jupiter).
How often do occultations between planets occur?