The only minor potential problem I can see is that you might end up having to price IAH-EZE-IAH as an H fare rather than SJO-EZE-SJO as an H fare and it might be more expensive that way. Certainly worth asking/trying, but don't be surprised if it doesn't work out the way you hope.
Code:
SJO San Jose Juan Santamaria Int'l CR [MROC]
EZE Buenos Aires Ministro Pistarini BA AR [SAEZ]
RT Jan-Dec
Carrier From To Fare Cur Expiry Min Max Fare Basis
--------- ------ ---- --------- ---- --------- ---- ---- ----------
CO SJO EZE 1118 USD 60 HE60CM
CO SJO EZE 1218 USD 90 HE90CM
Code:
IAH Houston George Bush Intercnt'l TX US [KIAH]
EZE Buenos Aires Ministro Pistarini BA AR [SAEZ]
RT Jan-Dec
Carrier From To Fare Cur Expiry Min Max Fare Basis
--------- ------ ---- --------- ---- --------- ---- ---- ----------
CO IAH EZE 2011 USD *** HR3SAN
CO IAH EZE 2064 USD *** HXR0SAN
CO IAH EZE 2117 USD *** HR0SAN
CO IAH EZE 3399 USD HOX