Problem with the "difference term" in upconversion module

Hello,

to realize upconversion from about "1MHz...100MHz" to "100MHz...26.5GHz" we chose four different mixers.
Anyway, due to the low IF frequncy, we have problems with the "difference term" of the upconversion.

IF = 50MHz with bandwidth=50MHz
LO=2GHz

leads to
RF1= 2GHZ+50MHz
and
the parasitic
RF2=2GHz-50MHz

Is there another possibility than filtering to solve the problem ?

Thanks