sed + search word with strings and replaced all word

I want to create with sed the following:

for example each word in the file that have the "ssss..." Should be replaced (all word) with target string as gggg

 echo "duwdbnhb ssssssmnfkejfnei" | sed s'/ssssss*/gggg/g'

 duwdbnhb ggggmnfkejfnei

should be:

 duwdbnhb gggg

remark - string could be with couple of "s" strings ( for example ss or sss or ssssss )

example:

 echo "duwdbnhb sssmnfkejfnei" | sed s'/s*/gggg/g'

 duwdbnhb gggg



 echo "duwdbnhb sssmnfdej3434bjhhji" | sed s'/s*/gggg/g'

 duwdbnhb gggg