4 way Cross fitting off of a 1 pipe steam riser??

I am starting an apartment renovation and the unit is on the first floor of a multistory building. The client would like to add a radiator to the existing 1 pipe steam system. The proposed rad will be on the opposite side of the riser as the existing rads. Can I replace the existing steam tee in the riser with a cross fitting to accomplish this without the risk of water hammer or anything else I may not see right now? Thanks in advance for any/all input.