You can add another activity in the manifest
<activity
android:name="ActivityA"
>
<intent-filter>
<action android:name="android.intent.action.VIEW" />
<category android:name="android.intent.category.DEFAULT" />
<category android:name="android.intent.category.BROWSABLE" />
<data
android:host="MYAPP"
android:scheme="oauth" />
</intent-filter>
</activity>
<activity
android:name="ActivityB"
>
<intent-filter>
<action android:name="android.intent.action.VIEW" />
<category android:name="android.intent.category.DEFAULT" />
<category android:name="android.intent.category.BROWSABLE" />
<data
android:host="MYAPP2"
android:scheme="oauth" />
</intent-filter>
</activity>
When you call the authentication url, set a different callback url If you are using Twitter4J, this is what it will look like.
requestToken = twitter.getOAuthRequestToken("oauth/MYAPP");
authenticationUrl = requestToken.getAuthenticationURL();
startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse(authenticationUrl)));
in the second activity,
requestToken = twitter.getOAuthRequestToken("oauth/MYAPP2");
authenticationUrl = requestToken.getAuthenticationURL();
startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse(authenticationUrl)));
Hope this helps.