i have csv as below

col1,col2,col3,col4,col5

1,val1,57,val1,TRUE ,val2,,val2,
,val3,,val3,
,val4,,val4,
,val5,,val5,
2,val1,878,val1,FALSE ,val2,,val2,
,val3,,val3,
,val4,,val4,
,val5,,val5,

i need to display the output using awk as below

col1,col2,col3,col4,col5

1,val1#val2#val3#val4#val5,57,val1#val2#val3#val4#val5,TRUE 2,val1#val2#val3#val4#val5,878,val1#val2#val3#val4#val5,FALSE

i have csv as below

col1,col2,col3,col4,col5 1,val1,57,val1,TRUE ,val2,,val2, ,val3,,val3, ,val4,,val4, ,val5,,val5, 2,val1,878,val1,FALSE ,val2,,val2, ,val3,,val3, ,val4,,val4, ,val5,,val5, 

i need to display the output using awk as below

col1,col2,col3,col4,col5 1,val1#val2#val3#val4#val5,57,val1#val2#val3#val4#val5,TRUE 2,val1#val2#val3#val4#val5,878,val1#val2#val3#val4#val5,FALSE