Evaluating multiple expression using th:if in Thymeleaf

I am wondering what the correct syntax for multiple expressions within th:if in Thymeleaf is. So far I have something like this:

<a style="color:blue" th:href="@{/approveAndJoin/{name}(name=${outbox.receiverName})}" th:if="${not #strings.startsWith(outbox.status, 'P')}">Join Team?!</a>

What would the correct syntax be to do something like this: (Pseudo code)

th:if="${not #strings.startsWith(outbox.status, 'P') && #strings.startsWith(inbox.status, 'A'}"

I have read through the various manuals but have not discovered how to do this.