Complex sentence: Saint Vincent and the Grenadines Rugby Union Football Club represents the Saint Vincent and the Grenadines in international rugby union football as the national team and is also the governing body for rugby in Saint Vincent and the Grenadines which is considered a tier-three rugby nation.
Split into simpler sentences: Saint Vincent and the Grenadines Rugby Union Football Club represents the Saint Vincent and the Grenadines in international rugby union football. The club is the "de facto" national team and also acts as the governing body for rugby in Saint Vincent and the Grenadines, which is considered a tier-three rugby nation.