How to avoid mulitple ant calls

[Sekar Varatharajan]

Guys,

<antcall target="checkoutWithTag" >
                <param name="projectName" value="AAA"/>
                <param name="tag" value="release_1"/>
</antcall>

<antcall target="checkoutWithTag" >
                <param name="projectName" value="BB"/>
                <param name="tag" value="release_12"/>
</antcall>



<target name="checkoutWithTag" >
                Custom Tag which accepts projectName and tag as its parameters.
</checkoutAndDeploy>



So now i want to pass on the values for "projectName" and "tag" not
hardcoded inside the antcall but would like to read it from some where else
i.e properties file.
How do i do it without making soo many ant calls.....maybe something like
loop where i can read the projectName everytime and pass it to the target??
If yes then how do i make loops in Ant???

Any Suggestions???