I'm not 100% sure, but as far as I know this is not (easily?) possible. The addresses used for sending/receiving payments are created using your initial private key (THe 20 word long seed) in a deterministic way. When creating a new wallet with this pivate key, the same addresses are generated.
It is not possible to guess your private key having one or more of your addresses. I think it's also not possible to guess which private key has generated the addresses.
You should use an address only for one transaction.
Possible duplicate of http://bitcoin.stackexchange.com/questions/7447/is-it-possible-to-figure-out-whether-two-addresses-are-in-the-same-wallet
– morsecoder – 2016-01-26T16:01:16.910Related: http://bitcoin.stackexchange.com/questions/52/how-anonymous-are-bitcoin-transactions
– morsecoder – 2016-01-26T16:01:47.227