Group dot separated sting to fixed format

can someone give me some pointers for this?
I have dot -separate tree hierarchy

323-060
        040
           030

As a result, I have the next lines

"323-060"
"323-060.040"
"323-060.040.030"

So, in the input I got the next lines:
“323-060″,
323-060.040″,
323-060.040.030”,

323-060.088″,
323-060.088.020″,

323-060.010″,
323-060.010.080″,
323-060.010.080.020″,
323-060.010.080.060″

As a result I have to get the next:

323-060323-060.040323-060.040.030
323-060323-060.088323-060.088.020
323-060323-060.010323-060.010.080323-060.010.080.020
323-060323-060.010323-060.010.080323-060.010.080.060

How to do it in Java ?