The words in Set I have something in common, as do the words in Set II. Additionally, the two Sets are related to each other in a certain way. Can you determine the relationships?

Set I
ITCH
ORES
UTTER
RANGE
AIRWAY

Set II
BUR
TRUE
HONE
CLOSE
AGAIN

HINT:
The same two letters will change the words in both sets into new ones.

Answers:

The words in Set I can be preceded by ST, and the words in Set II can be followed by ST:

Set I
STITCH
STORES
STUTTER
STRANGE
STAIRWAY

Set II
BURST
TRUEST
HONEST
CLOSEST
AGAINST