Sample code to set target audience for Each items in the Spfx webpart

You can check if current user is part of specific group using below code and show the particular section according to it.

this.context.spHttpClient.get(this.context.pageContext.site.absoluteUrl + "_api/Web/CurrentUser/Groups",
SPHttpClient.configurations.v1)
.then((groupResponse: SPHttpClientResponse) => {
groupResponse.json().then((groupsData: any) => {
var groups = groupsData.value;
groups.forEach(group => {
if (group.Title == "**your group name**") {
// your code
}
});
});
});