Applying multiple binds to an element...

What's the best way to output multiple validations to the same element using
bind statements? I have a case where a user might apply multiple validation
rules (like is it a phone number and does it match a pattern.) 

For example:
<xform:bind 
	ref="//xform:model/xf:instance/homePhone"
	required="true"
	type="valid:PHONE"
	/>
<xform:bind 
	ref="//xform:model/xf:instance/homePhone"
	required="true"
	type="valid:REGEX"
	/>

It doesn't seem right to have the required property on both. Is there a
better way to approach this--without combining my two validation procedures
into one?

Thanks,
Dan