How to define reference category for comparing dummyvariables in FE regression?


My timeseries is from 1985 to 2005, and my intention is to view an relationship after 1995 to 2005 with comparing two dummyvariables. And using units as referencecategory. My problem is therefore related to that i am using an Fixed Effects-estimate, and cannot include any timeinvariant variables.

The command; "data$dummy <- 0
data$dummy[data$COUNTRY=='unit' & data$TIME >= year] <- 1", will create the former timespan (1985 - 1995) as the referencecategory for each of the two dummies, and not the units which are not included in the process of creating the dummyvariables.

Therefore, i am wondering if there is an way to compare two dummys after an year in reference to units when using an FE estimate ?