I te tau 1929, ka wehe atu a Groves ki Nicaragua hei kawenga mo tetahi kamupene o te 1st Engineers hei waahanga o te haerenga ko te kaupapa ko te tirotiro mo te Inter-Oceanic Nicaragua Canal. Whai muri i te ru o Nikaragua i te tau 1931
, I riro i a Groves te kawenga mo te punaha tuku wai a Managua, na te mea i whakawhiwhia ki a ia te Tohu Perehitini o Nicaragua mo te Tohu Tohu. I whakatairangahia a Groves ki te rangatira i te 20 o Oketopa 1934. I haere ia ki te Kura Whakahaere me te Kaimahi Matua i Fort Leavenworth, Kansas, i te 1935 me te 1936, i muri mai ka tukuna ia ki Kansas City, Missouri, hei kaiawhina ki te rangatira o te Missouri River Division. I te tau 1938 me te 1939 i haere ia ki te Whare Wānanga o te Army War. I te 1 o Hōngongoi 1939, i tukuna ia ki te Tari Whawhai General Staff i Washington, DC.