Apologies for the confusing post title. I am returning the value in column B of the row in Master (worksheet) where the values of columns A and H or A and G match those of columns R and O or R and N in Usage Staging (worksheet), respectively, to column S of Usage Staging using the following array formula (relevant part in blue):

{=IF($R2="","",IF($R2="Member Not in PS","Member Not in Master",IF(VLOOKUP($R2,'Master'!$A$2:$J$20000,2,FALSE)="","No Company Name",IF(P2="USA",IF(ISERROR(INDEX('Master'!$B$2:$B$20000,MATCH('Usage Staging'!$R2&'Usage Staging'!$O2,'Master'!$A$2:$A$20000&'Master'!$H$2:$H$20000,0))),"No Exact Member ID & State Pair Match",INDEX('Master'!$B$2:$B$20000,MATCH('Usage Staging'!$R2&'Usage Staging'!$O2,'Master'!$A$2:$A$20000&'Master'!$H$2:$H$20000,0))),IF(ISERROR(INDEX('Master'!$B$2:$B$20000,MATCH('Usage Staging'!$R2&'Usage Staging'!$N2,'Master'!$A$2:$A$20000&'Master'!$G$2:$G$20000,0))),"No Exact Member ID & City Pair Match",INDEX('Master'!$B$2:$B$20000,MATCH('Usage Staging'!$R2&'Usage Staging'!$N2,'Master'!$A$2:$A$20000&'Master'!$G$2:$G$20000,0)))))))}

This works fine, but I'd like to tweak it by making the H to O and G to N matches work where the string in H is found in O and the string in G is found in N; in other words, I'd like partial matching to work, as long as H and O are completeley found in G and N, respectively.

Thanks!